<!DOCTYPE html>
<html lang="zh-CN">
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width,initial-scale=1">
    <title> </title>
    <meta name="generator" content="VuePress 1.8.2">
    <link rel="icon" href="/favicon.ico">
    <meta name="description" content=" ">
    <meta name="Description" content="Apache IoTDB: Time Series Database for IoT">
    <meta name="Keywords" content="TSDB, time series, time series database, IoTDB, IoT database, IoT data management,时序数据库, 时间序列管理, IoTDB, 物联网数据库, 实时数据库, 物联网数据管理, 物联网数据">
    <meta name="baidu-site-verification" content="wfKETzB3OT">
    <meta name="google-site-verification" content="mZWAoRY0yj_HAr-s47zHCGHzx5Ju-RVm5wDbPnwQYFo">
    
    <link rel="preload" href="/assets/css/0.styles.f7fca28c.css" as="style"><link rel="preload" href="/assets/js/app.13a2c569.js" as="script"><link rel="preload" href="/assets/js/3.7fccac46.js" as="script"><link rel="preload" href="/assets/js/552.2086fbe8.js" as="script"><link rel="prefetch" href="/assets/js/10.61872ae5.js"><link rel="prefetch" href="/assets/js/100.cd07fbb4.js"><link rel="prefetch" href="/assets/js/101.7b887a78.js"><link rel="prefetch" href="/assets/js/102.888ac47b.js"><link rel="prefetch" href="/assets/js/103.edff174f.js"><link rel="prefetch" href="/assets/js/104.f049af68.js"><link rel="prefetch" href="/assets/js/105.f7c9efe5.js"><link rel="prefetch" href="/assets/js/106.2ba6adb1.js"><link rel="prefetch" href="/assets/js/107.d676f1a5.js"><link rel="prefetch" href="/assets/js/108.c3799be3.js"><link rel="prefetch" href="/assets/js/109.22c12024.js"><link rel="prefetch" href="/assets/js/11.a080efae.js"><link rel="prefetch" href="/assets/js/110.e988abeb.js"><link rel="prefetch" href="/assets/js/111.70e5507a.js"><link rel="prefetch" href="/assets/js/112.7e40d306.js"><link rel="prefetch" href="/assets/js/113.5f9eed75.js"><link rel="prefetch" href="/assets/js/114.12676666.js"><link rel="prefetch" href="/assets/js/115.de7d0451.js"><link rel="prefetch" href="/assets/js/116.9241daf0.js"><link rel="prefetch" href="/assets/js/117.f1572c4d.js"><link rel="prefetch" href="/assets/js/118.e8829e92.js"><link rel="prefetch" href="/assets/js/119.0b0c33f8.js"><link rel="prefetch" href="/assets/js/12.454ce3d8.js"><link rel="prefetch" href="/assets/js/120.0bf117bb.js"><link rel="prefetch" href="/assets/js/121.4ecd8344.js"><link rel="prefetch" href="/assets/js/122.f3a6aea0.js"><link rel="prefetch" href="/assets/js/123.4945f91b.js"><link rel="prefetch" href="/assets/js/124.41877e73.js"><link rel="prefetch" href="/assets/js/125.85775a08.js"><link rel="prefetch" href="/assets/js/126.60bc16f9.js"><link rel="prefetch" href="/assets/js/127.64f37463.js"><link rel="prefetch" href="/assets/js/128.bf1e94f3.js"><link rel="prefetch" href="/assets/js/129.66d9bb2b.js"><link rel="prefetch" href="/assets/js/13.c58bffc8.js"><link rel="prefetch" href="/assets/js/130.59874ca0.js"><link rel="prefetch" href="/assets/js/131.f9d5e913.js"><link rel="prefetch" href="/assets/js/132.a7e3ad59.js"><link rel="prefetch" href="/assets/js/133.25bc611b.js"><link rel="prefetch" href="/assets/js/134.031b80a3.js"><link rel="prefetch" href="/assets/js/135.63c51cd4.js"><link rel="prefetch" href="/assets/js/136.3035a447.js"><link rel="prefetch" href="/assets/js/137.f04f53d6.js"><link rel="prefetch" href="/assets/js/138.0d77670b.js"><link rel="prefetch" href="/assets/js/139.a4687aa3.js"><link rel="prefetch" href="/assets/js/14.939be0f9.js"><link rel="prefetch" href="/assets/js/140.1c3b9c8e.js"><link rel="prefetch" href="/assets/js/141.85a83839.js"><link rel="prefetch" href="/assets/js/142.7d8ad627.js"><link rel="prefetch" href="/assets/js/143.fbdc020f.js"><link rel="prefetch" href="/assets/js/144.d6b9f34b.js"><link rel="prefetch" href="/assets/js/145.4a65f13c.js"><link rel="prefetch" href="/assets/js/146.d6f1ef22.js"><link rel="prefetch" href="/assets/js/147.e33fe78c.js"><link rel="prefetch" href="/assets/js/148.1f001b51.js"><link rel="prefetch" href="/assets/js/149.d802d76b.js"><link rel="prefetch" href="/assets/js/15.843fe861.js"><link rel="prefetch" href="/assets/js/150.bf6e4446.js"><link rel="prefetch" href="/assets/js/151.1a3a9ecf.js"><link rel="prefetch" href="/assets/js/152.ca32b0c3.js"><link rel="prefetch" href="/assets/js/153.74bb0871.js"><link rel="prefetch" href="/assets/js/154.2e0647d0.js"><link rel="prefetch" href="/assets/js/155.d1c42f9d.js"><link rel="prefetch" href="/assets/js/156.dd3ef885.js"><link rel="prefetch" href="/assets/js/157.d0fa5d7e.js"><link rel="prefetch" href="/assets/js/158.d8ac80b6.js"><link rel="prefetch" href="/assets/js/159.7daff5e5.js"><link rel="prefetch" href="/assets/js/16.8d6c0ada.js"><link rel="prefetch" href="/assets/js/160.334e1792.js"><link rel="prefetch" href="/assets/js/161.ea35ffd3.js"><link rel="prefetch" href="/assets/js/162.a3e43ef6.js"><link rel="prefetch" href="/assets/js/163.63e5a86d.js"><link rel="prefetch" href="/assets/js/164.014d76e1.js"><link rel="prefetch" href="/assets/js/165.93a410f4.js"><link rel="prefetch" href="/assets/js/166.a5f56f78.js"><link rel="prefetch" href="/assets/js/167.51507116.js"><link rel="prefetch" href="/assets/js/168.34704422.js"><link rel="prefetch" href="/assets/js/169.0251848a.js"><link rel="prefetch" href="/assets/js/17.efe29df6.js"><link rel="prefetch" href="/assets/js/170.f9084320.js"><link rel="prefetch" href="/assets/js/171.ba1d2df7.js"><link rel="prefetch" href="/assets/js/172.8a7cd300.js"><link rel="prefetch" href="/assets/js/173.4d45b322.js"><link rel="prefetch" href="/assets/js/174.14ce1f9d.js"><link rel="prefetch" href="/assets/js/175.8ba92c6d.js"><link rel="prefetch" href="/assets/js/176.f83d84c6.js"><link rel="prefetch" href="/assets/js/177.e3ca589e.js"><link rel="prefetch" href="/assets/js/178.e26e2799.js"><link rel="prefetch" href="/assets/js/179.80f9f4ee.js"><link rel="prefetch" href="/assets/js/18.ec2f64fe.js"><link rel="prefetch" href="/assets/js/180.16830f5a.js"><link rel="prefetch" href="/assets/js/181.6c2dd09c.js"><link rel="prefetch" href="/assets/js/182.4b20bd4d.js"><link rel="prefetch" href="/assets/js/183.f1a9f3d0.js"><link rel="prefetch" href="/assets/js/184.4e828571.js"><link rel="prefetch" href="/assets/js/185.be70dd25.js"><link rel="prefetch" href="/assets/js/186.ddb365dd.js"><link rel="prefetch" href="/assets/js/187.f66f7f93.js"><link rel="prefetch" href="/assets/js/188.6a88c397.js"><link rel="prefetch" href="/assets/js/189.28897e83.js"><link rel="prefetch" href="/assets/js/19.e46591ce.js"><link rel="prefetch" href="/assets/js/190.a85849f1.js"><link rel="prefetch" href="/assets/js/191.9fd2f58a.js"><link rel="prefetch" href="/assets/js/192.1f3b6ca8.js"><link rel="prefetch" href="/assets/js/193.50aae911.js"><link rel="prefetch" href="/assets/js/194.e166c10d.js"><link rel="prefetch" href="/assets/js/195.1a1f9e4a.js"><link rel="prefetch" href="/assets/js/196.072c3ce0.js"><link rel="prefetch" href="/assets/js/197.36a569b3.js"><link rel="prefetch" href="/assets/js/198.ef935ad0.js"><link rel="prefetch" href="/assets/js/199.0614cb86.js"><link rel="prefetch" href="/assets/js/20.335cca54.js"><link rel="prefetch" href="/assets/js/200.e9583ef5.js"><link rel="prefetch" href="/assets/js/201.b4147cd7.js"><link rel="prefetch" href="/assets/js/202.655454f0.js"><link rel="prefetch" href="/assets/js/203.f00817d3.js"><link rel="prefetch" href="/assets/js/204.6f3bfde7.js"><link rel="prefetch" href="/assets/js/205.01353228.js"><link rel="prefetch" href="/assets/js/206.6d142fbd.js"><link rel="prefetch" href="/assets/js/207.f4f1071e.js"><link rel="prefetch" href="/assets/js/208.497a96dd.js"><link rel="prefetch" href="/assets/js/209.f813458b.js"><link rel="prefetch" href="/assets/js/21.8c3060b4.js"><link rel="prefetch" href="/assets/js/210.a45cff9c.js"><link rel="prefetch" href="/assets/js/211.5af25a9e.js"><link rel="prefetch" href="/assets/js/212.28908eba.js"><link rel="prefetch" href="/assets/js/213.93ca2d15.js"><link rel="prefetch" href="/assets/js/214.674059a0.js"><link rel="prefetch" href="/assets/js/215.d03b45be.js"><link rel="prefetch" href="/assets/js/216.64aebb7b.js"><link rel="prefetch" href="/assets/js/217.fd00686a.js"><link rel="prefetch" href="/assets/js/218.1bc04620.js"><link rel="prefetch" href="/assets/js/219.f93bf7a6.js"><link rel="prefetch" href="/assets/js/22.d30695a0.js"><link rel="prefetch" href="/assets/js/220.2a4ece08.js"><link rel="prefetch" href="/assets/js/221.42c08a34.js"><link rel="prefetch" href="/assets/js/222.598decbc.js"><link rel="prefetch" href="/assets/js/223.fb835c56.js"><link rel="prefetch" href="/assets/js/224.54855e83.js"><link rel="prefetch" href="/assets/js/225.3d94f453.js"><link rel="prefetch" href="/assets/js/226.2468bc8c.js"><link rel="prefetch" href="/assets/js/227.140240fe.js"><link rel="prefetch" href="/assets/js/228.eddc9919.js"><link rel="prefetch" href="/assets/js/229.7f4447ca.js"><link rel="prefetch" href="/assets/js/23.c21377c0.js"><link rel="prefetch" href="/assets/js/230.5f994ca9.js"><link rel="prefetch" href="/assets/js/231.2c87bfd0.js"><link rel="prefetch" href="/assets/js/232.491ed5e5.js"><link rel="prefetch" href="/assets/js/233.12245eff.js"><link rel="prefetch" href="/assets/js/234.da21e051.js"><link rel="prefetch" href="/assets/js/235.ad48abdb.js"><link rel="prefetch" href="/assets/js/236.3a295dec.js"><link rel="prefetch" href="/assets/js/237.84ff9c9b.js"><link rel="prefetch" href="/assets/js/238.627264aa.js"><link rel="prefetch" href="/assets/js/239.da37d07f.js"><link rel="prefetch" href="/assets/js/24.cc9cb1b0.js"><link rel="prefetch" href="/assets/js/240.f14cafaf.js"><link rel="prefetch" href="/assets/js/241.14ce6be3.js"><link rel="prefetch" href="/assets/js/242.9b6f988e.js"><link rel="prefetch" href="/assets/js/243.52a22828.js"><link rel="prefetch" href="/assets/js/244.41d248ca.js"><link rel="prefetch" href="/assets/js/245.1ba76fb4.js"><link rel="prefetch" href="/assets/js/246.cf8b4383.js"><link rel="prefetch" href="/assets/js/247.72a2b769.js"><link rel="prefetch" href="/assets/js/248.818a247a.js"><link rel="prefetch" href="/assets/js/249.095696b0.js"><link rel="prefetch" href="/assets/js/25.6b7591da.js"><link rel="prefetch" href="/assets/js/250.40e471ff.js"><link rel="prefetch" href="/assets/js/251.dd9c98c7.js"><link rel="prefetch" href="/assets/js/252.322c13d1.js"><link rel="prefetch" href="/assets/js/253.a74589e8.js"><link rel="prefetch" href="/assets/js/254.c0b11411.js"><link rel="prefetch" href="/assets/js/255.a31b5869.js"><link rel="prefetch" href="/assets/js/256.65a4a631.js"><link rel="prefetch" href="/assets/js/257.6c275bae.js"><link rel="prefetch" href="/assets/js/258.29edab81.js"><link rel="prefetch" href="/assets/js/259.a44df503.js"><link rel="prefetch" href="/assets/js/26.607efd21.js"><link rel="prefetch" href="/assets/js/260.e829b6db.js"><link rel="prefetch" href="/assets/js/261.b0af8f05.js"><link rel="prefetch" href="/assets/js/262.16e28745.js"><link rel="prefetch" href="/assets/js/263.bd55ccfb.js"><link rel="prefetch" href="/assets/js/264.542e2765.js"><link rel="prefetch" href="/assets/js/265.7fbdc730.js"><link rel="prefetch" href="/assets/js/266.d5354498.js"><link rel="prefetch" href="/assets/js/267.4fa2b728.js"><link rel="prefetch" href="/assets/js/268.d8050f72.js"><link rel="prefetch" href="/assets/js/269.860f97fb.js"><link rel="prefetch" href="/assets/js/27.9e25f953.js"><link rel="prefetch" href="/assets/js/270.d4607b7c.js"><link rel="prefetch" href="/assets/js/271.32e58adb.js"><link rel="prefetch" href="/assets/js/272.16c3fb95.js"><link rel="prefetch" href="/assets/js/273.c6b08152.js"><link rel="prefetch" href="/assets/js/274.ad95be0e.js"><link rel="prefetch" href="/assets/js/275.5f216f81.js"><link rel="prefetch" href="/assets/js/276.d92d5f9c.js"><link rel="prefetch" href="/assets/js/277.3c17ccd3.js"><link rel="prefetch" href="/assets/js/278.0c8cae32.js"><link rel="prefetch" href="/assets/js/279.dcd3c96d.js"><link rel="prefetch" href="/assets/js/28.de5fbffd.js"><link rel="prefetch" href="/assets/js/280.5bf9735e.js"><link rel="prefetch" href="/assets/js/281.ede2be97.js"><link rel="prefetch" href="/assets/js/282.39c15f23.js"><link rel="prefetch" href="/assets/js/283.e1c65b67.js"><link rel="prefetch" href="/assets/js/284.f3de51ff.js"><link rel="prefetch" href="/assets/js/285.07e0a191.js"><link rel="prefetch" href="/assets/js/286.d67567fb.js"><link rel="prefetch" href="/assets/js/287.b1ba4806.js"><link rel="prefetch" href="/assets/js/288.58158555.js"><link rel="prefetch" href="/assets/js/289.1070b060.js"><link rel="prefetch" href="/assets/js/29.a31435b1.js"><link rel="prefetch" href="/assets/js/290.4c4ff771.js"><link rel="prefetch" href="/assets/js/291.05d7dacb.js"><link rel="prefetch" href="/assets/js/292.c6b2ff86.js"><link rel="prefetch" href="/assets/js/293.dd9ac7d5.js"><link rel="prefetch" href="/assets/js/294.0ad93593.js"><link rel="prefetch" href="/assets/js/295.10a4d3cc.js"><link rel="prefetch" href="/assets/js/296.8dd679cd.js"><link rel="prefetch" href="/assets/js/297.958699f4.js"><link rel="prefetch" href="/assets/js/298.db46105e.js"><link rel="prefetch" href="/assets/js/299.98788b55.js"><link rel="prefetch" href="/assets/js/30.2a46f39a.js"><link rel="prefetch" href="/assets/js/300.7171d756.js"><link rel="prefetch" href="/assets/js/301.a327ccf9.js"><link rel="prefetch" href="/assets/js/302.eddbbf46.js"><link rel="prefetch" href="/assets/js/303.011a1812.js"><link rel="prefetch" href="/assets/js/304.b3d2809d.js"><link rel="prefetch" href="/assets/js/305.c7964909.js"><link rel="prefetch" href="/assets/js/306.1deec4af.js"><link rel="prefetch" href="/assets/js/307.99fa3519.js"><link rel="prefetch" href="/assets/js/308.71ea079a.js"><link rel="prefetch" href="/assets/js/309.cb8ba2cc.js"><link rel="prefetch" href="/assets/js/31.fab44020.js"><link rel="prefetch" href="/assets/js/310.0aa0c0b3.js"><link rel="prefetch" href="/assets/js/311.b4083583.js"><link rel="prefetch" href="/assets/js/312.f482271f.js"><link rel="prefetch" href="/assets/js/313.f9d39443.js"><link rel="prefetch" href="/assets/js/314.a2d1f5e3.js"><link rel="prefetch" href="/assets/js/315.3fb90439.js"><link rel="prefetch" href="/assets/js/316.c0f044f0.js"><link rel="prefetch" href="/assets/js/317.dddc1a4a.js"><link rel="prefetch" href="/assets/js/318.3254e19d.js"><link rel="prefetch" href="/assets/js/319.91dfc2a0.js"><link rel="prefetch" href="/assets/js/32.8f287f6a.js"><link rel="prefetch" href="/assets/js/320.106bf450.js"><link rel="prefetch" href="/assets/js/321.82f34bcd.js"><link rel="prefetch" href="/assets/js/322.eeef9dc9.js"><link rel="prefetch" href="/assets/js/323.c75babb0.js"><link rel="prefetch" href="/assets/js/324.d54a6492.js"><link rel="prefetch" href="/assets/js/325.76b7273b.js"><link rel="prefetch" href="/assets/js/326.4e8805ea.js"><link rel="prefetch" href="/assets/js/327.d62d13a8.js"><link rel="prefetch" href="/assets/js/328.3ca46a63.js"><link rel="prefetch" href="/assets/js/329.6a107c33.js"><link rel="prefetch" href="/assets/js/33.5af74851.js"><link rel="prefetch" href="/assets/js/330.b4d8ab0b.js"><link rel="prefetch" href="/assets/js/331.618f6def.js"><link rel="prefetch" href="/assets/js/332.3d4c9612.js"><link rel="prefetch" href="/assets/js/333.117e8020.js"><link rel="prefetch" href="/assets/js/334.2fe8d9b7.js"><link rel="prefetch" href="/assets/js/335.0c31be40.js"><link rel="prefetch" href="/assets/js/336.351485be.js"><link rel="prefetch" href="/assets/js/337.5a7bfc08.js"><link rel="prefetch" href="/assets/js/338.6c7d249f.js"><link rel="prefetch" href="/assets/js/339.682690f4.js"><link rel="prefetch" href="/assets/js/34.5dfe1291.js"><link rel="prefetch" href="/assets/js/340.b5cdb42e.js"><link rel="prefetch" href="/assets/js/341.fb27a06c.js"><link rel="prefetch" href="/assets/js/342.8e2f44ea.js"><link rel="prefetch" href="/assets/js/343.f7bec8a4.js"><link rel="prefetch" href="/assets/js/344.738defee.js"><link rel="prefetch" href="/assets/js/345.e716023b.js"><link rel="prefetch" href="/assets/js/346.0838d343.js"><link rel="prefetch" href="/assets/js/347.ea14c3a2.js"><link rel="prefetch" href="/assets/js/348.bf57b876.js"><link rel="prefetch" href="/assets/js/349.c51797f5.js"><link rel="prefetch" href="/assets/js/35.0a7b7db7.js"><link rel="prefetch" href="/assets/js/350.9f56c7ca.js"><link rel="prefetch" href="/assets/js/351.6b7a1c79.js"><link rel="prefetch" href="/assets/js/352.4cc5a7ff.js"><link rel="prefetch" href="/assets/js/353.76cd6b37.js"><link rel="prefetch" href="/assets/js/354.d811ac0e.js"><link rel="prefetch" href="/assets/js/355.c5ffb190.js"><link rel="prefetch" href="/assets/js/356.29e3e2cd.js"><link rel="prefetch" href="/assets/js/357.359b4fdf.js"><link rel="prefetch" href="/assets/js/358.02bee4be.js"><link rel="prefetch" href="/assets/js/359.20c5d24f.js"><link rel="prefetch" href="/assets/js/36.8a8c44ca.js"><link rel="prefetch" href="/assets/js/360.42ffe98f.js"><link rel="prefetch" href="/assets/js/361.9aa30956.js"><link rel="prefetch" href="/assets/js/362.b3bfe78e.js"><link rel="prefetch" href="/assets/js/363.715dceba.js"><link rel="prefetch" href="/assets/js/364.1bf938a5.js"><link rel="prefetch" href="/assets/js/365.7712ed2c.js"><link rel="prefetch" href="/assets/js/366.3b48b0f0.js"><link rel="prefetch" href="/assets/js/367.e3bf3b9c.js"><link rel="prefetch" href="/assets/js/368.ee547bda.js"><link rel="prefetch" href="/assets/js/369.736a646d.js"><link rel="prefetch" href="/assets/js/37.7ed1a8d1.js"><link rel="prefetch" href="/assets/js/370.0cd94992.js"><link rel="prefetch" href="/assets/js/371.9c126e32.js"><link rel="prefetch" href="/assets/js/372.e0dae98b.js"><link rel="prefetch" href="/assets/js/373.3f497d20.js"><link rel="prefetch" href="/assets/js/374.8265b294.js"><link rel="prefetch" href="/assets/js/375.1691bf1a.js"><link rel="prefetch" href="/assets/js/376.d1bc249a.js"><link rel="prefetch" href="/assets/js/377.a70ed1ed.js"><link rel="prefetch" href="/assets/js/378.06ee3a0c.js"><link rel="prefetch" href="/assets/js/379.d482914b.js"><link rel="prefetch" href="/assets/js/38.8d2f9b02.js"><link rel="prefetch" href="/assets/js/380.772ce624.js"><link rel="prefetch" href="/assets/js/381.272a5a56.js"><link rel="prefetch" href="/assets/js/382.538e2883.js"><link rel="prefetch" href="/assets/js/383.27a09ab5.js"><link rel="prefetch" href="/assets/js/384.f6699047.js"><link rel="prefetch" href="/assets/js/385.1753768d.js"><link rel="prefetch" href="/assets/js/386.4a939926.js"><link rel="prefetch" href="/assets/js/387.b6fc5efc.js"><link rel="prefetch" href="/assets/js/388.39561bad.js"><link rel="prefetch" href="/assets/js/389.39d88d6c.js"><link rel="prefetch" href="/assets/js/39.977e55a2.js"><link rel="prefetch" href="/assets/js/390.257ba104.js"><link rel="prefetch" href="/assets/js/391.7fee02e7.js"><link rel="prefetch" href="/assets/js/392.d06b100d.js"><link rel="prefetch" href="/assets/js/393.9a381cee.js"><link rel="prefetch" href="/assets/js/394.ff541e95.js"><link rel="prefetch" href="/assets/js/395.1762634a.js"><link rel="prefetch" href="/assets/js/396.18935752.js"><link rel="prefetch" href="/assets/js/397.3b471025.js"><link rel="prefetch" href="/assets/js/398.c19c7de2.js"><link rel="prefetch" href="/assets/js/399.ff63d0ee.js"><link rel="prefetch" href="/assets/js/4.b5d5c8b1.js"><link rel="prefetch" href="/assets/js/40.6f6fb483.js"><link rel="prefetch" href="/assets/js/400.9512b32d.js"><link rel="prefetch" href="/assets/js/401.0dd750ee.js"><link rel="prefetch" href="/assets/js/402.89f4cfc1.js"><link rel="prefetch" href="/assets/js/403.03cab865.js"><link rel="prefetch" href="/assets/js/404.e149b178.js"><link rel="prefetch" href="/assets/js/405.5757c50b.js"><link rel="prefetch" href="/assets/js/406.275df76e.js"><link rel="prefetch" href="/assets/js/407.60ff3fd6.js"><link rel="prefetch" href="/assets/js/408.a3278547.js"><link rel="prefetch" href="/assets/js/409.82295bb0.js"><link rel="prefetch" href="/assets/js/41.f1dd1831.js"><link rel="prefetch" href="/assets/js/410.4908ddb7.js"><link rel="prefetch" href="/assets/js/411.a1668ba1.js"><link rel="prefetch" href="/assets/js/412.5f32829d.js"><link rel="prefetch" href="/assets/js/413.2073ec9e.js"><link rel="prefetch" href="/assets/js/414.3b925d0b.js"><link rel="prefetch" href="/assets/js/415.60574f9c.js"><link rel="prefetch" href="/assets/js/416.a4d5a572.js"><link rel="prefetch" href="/assets/js/417.a50f9fce.js"><link rel="prefetch" href="/assets/js/418.b7270715.js"><link rel="prefetch" href="/assets/js/419.0160b711.js"><link rel="prefetch" href="/assets/js/42.2678c675.js"><link rel="prefetch" href="/assets/js/420.eceb0610.js"><link rel="prefetch" href="/assets/js/421.6d223975.js"><link rel="prefetch" href="/assets/js/422.37d30681.js"><link rel="prefetch" href="/assets/js/423.cdde877a.js"><link rel="prefetch" href="/assets/js/424.e6b188c7.js"><link rel="prefetch" href="/assets/js/425.07916e69.js"><link rel="prefetch" href="/assets/js/426.fe282fd2.js"><link rel="prefetch" href="/assets/js/427.091fed79.js"><link rel="prefetch" href="/assets/js/428.018905f3.js"><link rel="prefetch" href="/assets/js/429.1d2ba504.js"><link rel="prefetch" href="/assets/js/43.5a7a89fd.js"><link rel="prefetch" href="/assets/js/430.0fdf8f0b.js"><link rel="prefetch" href="/assets/js/431.820d99bb.js"><link rel="prefetch" href="/assets/js/432.43e9cb10.js"><link rel="prefetch" href="/assets/js/433.ae737c26.js"><link rel="prefetch" href="/assets/js/434.d0cb3962.js"><link rel="prefetch" href="/assets/js/435.f2e9a9f9.js"><link rel="prefetch" href="/assets/js/436.443e4e28.js"><link rel="prefetch" href="/assets/js/437.9b7c6a47.js"><link rel="prefetch" href="/assets/js/438.18a4a09c.js"><link rel="prefetch" href="/assets/js/439.4758b8a3.js"><link rel="prefetch" href="/assets/js/44.a3a87e08.js"><link rel="prefetch" href="/assets/js/440.bdc71883.js"><link rel="prefetch" href="/assets/js/441.9a6fe71c.js"><link rel="prefetch" href="/assets/js/442.e535e9e8.js"><link rel="prefetch" href="/assets/js/443.f4faca82.js"><link rel="prefetch" href="/assets/js/444.b473988e.js"><link rel="prefetch" href="/assets/js/445.78ac5385.js"><link rel="prefetch" href="/assets/js/446.f28a3730.js"><link rel="prefetch" href="/assets/js/447.b750645d.js"><link rel="prefetch" href="/assets/js/448.56a3f163.js"><link rel="prefetch" href="/assets/js/449.25ea6c3f.js"><link rel="prefetch" href="/assets/js/45.20484792.js"><link rel="prefetch" href="/assets/js/450.2c33d110.js"><link rel="prefetch" href="/assets/js/451.d3686bb4.js"><link rel="prefetch" href="/assets/js/452.9b77f332.js"><link rel="prefetch" href="/assets/js/453.0e2b7abb.js"><link rel="prefetch" href="/assets/js/454.afd716c0.js"><link rel="prefetch" href="/assets/js/455.fa872f53.js"><link rel="prefetch" href="/assets/js/456.f98176ff.js"><link rel="prefetch" href="/assets/js/457.a3a79351.js"><link rel="prefetch" href="/assets/js/458.9c216200.js"><link rel="prefetch" href="/assets/js/459.b8a82b6b.js"><link rel="prefetch" href="/assets/js/46.0681e191.js"><link rel="prefetch" href="/assets/js/460.eac79b47.js"><link rel="prefetch" href="/assets/js/461.a67af417.js"><link rel="prefetch" href="/assets/js/462.64546845.js"><link rel="prefetch" href="/assets/js/463.3a6bb1ff.js"><link rel="prefetch" href="/assets/js/464.74201d93.js"><link rel="prefetch" href="/assets/js/465.d85e632a.js"><link rel="prefetch" href="/assets/js/466.4fc5a167.js"><link rel="prefetch" href="/assets/js/467.07d37400.js"><link rel="prefetch" href="/assets/js/468.96853156.js"><link rel="prefetch" href="/assets/js/469.a50ae16a.js"><link rel="prefetch" href="/assets/js/47.ee804674.js"><link rel="prefetch" href="/assets/js/470.6cf56bd5.js"><link rel="prefetch" href="/assets/js/471.59484050.js"><link rel="prefetch" href="/assets/js/472.ddf64aa7.js"><link rel="prefetch" href="/assets/js/473.95a896c2.js"><link rel="prefetch" href="/assets/js/474.d7ef72d1.js"><link rel="prefetch" href="/assets/js/475.a4c47cfb.js"><link rel="prefetch" href="/assets/js/476.22ee9a93.js"><link rel="prefetch" href="/assets/js/477.b3ba19f3.js"><link rel="prefetch" href="/assets/js/478.864bbf5c.js"><link rel="prefetch" href="/assets/js/479.4a7a598c.js"><link rel="prefetch" href="/assets/js/48.de09959f.js"><link rel="prefetch" href="/assets/js/480.ccc08278.js"><link rel="prefetch" href="/assets/js/481.8f44cbac.js"><link rel="prefetch" href="/assets/js/482.7409d304.js"><link rel="prefetch" href="/assets/js/483.2aa7b9f7.js"><link rel="prefetch" href="/assets/js/484.fba5806a.js"><link rel="prefetch" href="/assets/js/485.a4fab60f.js"><link rel="prefetch" href="/assets/js/486.194aeb49.js"><link rel="prefetch" href="/assets/js/487.3ae9d4dc.js"><link rel="prefetch" href="/assets/js/488.37514b2b.js"><link rel="prefetch" href="/assets/js/489.31acbbe7.js"><link rel="prefetch" href="/assets/js/49.4b0fe119.js"><link rel="prefetch" href="/assets/js/490.4f33761a.js"><link rel="prefetch" href="/assets/js/491.de9b8f18.js"><link rel="prefetch" href="/assets/js/492.a78d9437.js"><link rel="prefetch" href="/assets/js/493.0adb4a52.js"><link rel="prefetch" href="/assets/js/494.d458943e.js"><link rel="prefetch" href="/assets/js/495.c7d99c90.js"><link rel="prefetch" href="/assets/js/496.eee126ee.js"><link rel="prefetch" href="/assets/js/497.22135cf5.js"><link rel="prefetch" href="/assets/js/498.8c2002be.js"><link rel="prefetch" href="/assets/js/499.b727490e.js"><link rel="prefetch" href="/assets/js/5.5a730a22.js"><link rel="prefetch" href="/assets/js/50.bebd6a8f.js"><link rel="prefetch" href="/assets/js/500.ebb3e02b.js"><link rel="prefetch" href="/assets/js/501.2ec75ec2.js"><link rel="prefetch" href="/assets/js/502.999d21ae.js"><link rel="prefetch" href="/assets/js/503.3415452d.js"><link rel="prefetch" href="/assets/js/504.cc899380.js"><link rel="prefetch" href="/assets/js/505.c001019c.js"><link rel="prefetch" href="/assets/js/506.ee989b6a.js"><link rel="prefetch" href="/assets/js/507.4316a0d6.js"><link rel="prefetch" href="/assets/js/508.b4b6e06c.js"><link rel="prefetch" href="/assets/js/509.97911be7.js"><link rel="prefetch" href="/assets/js/51.268a7400.js"><link rel="prefetch" href="/assets/js/510.0b6fdfff.js"><link rel="prefetch" href="/assets/js/511.90321f3b.js"><link rel="prefetch" href="/assets/js/512.e385bb2f.js"><link rel="prefetch" href="/assets/js/513.cf5a70ba.js"><link rel="prefetch" href="/assets/js/514.39c6f992.js"><link rel="prefetch" href="/assets/js/515.28c955af.js"><link rel="prefetch" href="/assets/js/516.9c03d034.js"><link rel="prefetch" href="/assets/js/517.50fb0287.js"><link rel="prefetch" href="/assets/js/518.f1fae3ac.js"><link rel="prefetch" href="/assets/js/519.0cd16549.js"><link rel="prefetch" href="/assets/js/52.b3ba6c43.js"><link rel="prefetch" href="/assets/js/520.e76896cc.js"><link rel="prefetch" href="/assets/js/521.4a4cf9d6.js"><link rel="prefetch" href="/assets/js/522.d83c5f3d.js"><link rel="prefetch" href="/assets/js/523.e4a7ecef.js"><link rel="prefetch" href="/assets/js/524.36e761c2.js"><link rel="prefetch" href="/assets/js/525.6317ecc2.js"><link rel="prefetch" href="/assets/js/526.4c2caa69.js"><link rel="prefetch" href="/assets/js/527.57c5ab09.js"><link rel="prefetch" href="/assets/js/528.8bb25375.js"><link rel="prefetch" href="/assets/js/529.afecb950.js"><link rel="prefetch" href="/assets/js/53.fe2684d4.js"><link rel="prefetch" href="/assets/js/530.75117402.js"><link rel="prefetch" href="/assets/js/531.8f5561eb.js"><link rel="prefetch" href="/assets/js/532.eb990d2c.js"><link rel="prefetch" href="/assets/js/533.504e3919.js"><link rel="prefetch" href="/assets/js/534.ea4173a0.js"><link rel="prefetch" href="/assets/js/535.bd37f9ad.js"><link rel="prefetch" href="/assets/js/536.e2e7eb7a.js"><link rel="prefetch" href="/assets/js/537.6c0a0dcb.js"><link rel="prefetch" href="/assets/js/538.0ce6d97b.js"><link rel="prefetch" href="/assets/js/539.6a2cada2.js"><link rel="prefetch" href="/assets/js/54.abc729a1.js"><link rel="prefetch" href="/assets/js/540.89a5b6ff.js"><link rel="prefetch" href="/assets/js/541.9a2d47d4.js"><link rel="prefetch" href="/assets/js/542.aeb476e7.js"><link rel="prefetch" href="/assets/js/543.f6480bc9.js"><link rel="prefetch" href="/assets/js/544.87ded954.js"><link rel="prefetch" href="/assets/js/545.dca671b2.js"><link rel="prefetch" href="/assets/js/546.0eea9df9.js"><link rel="prefetch" href="/assets/js/547.58eca1e8.js"><link rel="prefetch" href="/assets/js/548.69640134.js"><link rel="prefetch" href="/assets/js/549.9e2f3a65.js"><link rel="prefetch" href="/assets/js/55.98f29d94.js"><link rel="prefetch" href="/assets/js/550.344c4ac6.js"><link rel="prefetch" href="/assets/js/551.3935c91c.js"><link rel="prefetch" href="/assets/js/553.2aceadd3.js"><link rel="prefetch" href="/assets/js/554.1afd3108.js"><link rel="prefetch" href="/assets/js/555.16f1c7e8.js"><link rel="prefetch" href="/assets/js/556.2c9211d3.js"><link rel="prefetch" href="/assets/js/557.422b5e0d.js"><link rel="prefetch" href="/assets/js/558.1712976d.js"><link rel="prefetch" href="/assets/js/559.0052055f.js"><link rel="prefetch" href="/assets/js/56.fcf66dfb.js"><link rel="prefetch" href="/assets/js/560.e445bc77.js"><link rel="prefetch" href="/assets/js/561.cf50436f.js"><link rel="prefetch" href="/assets/js/562.e9d4e67d.js"><link rel="prefetch" href="/assets/js/563.15836f75.js"><link rel="prefetch" href="/assets/js/564.695e5d1f.js"><link rel="prefetch" href="/assets/js/565.e891cf80.js"><link rel="prefetch" href="/assets/js/566.1ef531d4.js"><link rel="prefetch" href="/assets/js/567.c04c597f.js"><link rel="prefetch" href="/assets/js/568.bbc2c743.js"><link rel="prefetch" href="/assets/js/569.7fca8ca1.js"><link rel="prefetch" href="/assets/js/57.a1d6e8e4.js"><link rel="prefetch" href="/assets/js/570.db8c6287.js"><link rel="prefetch" href="/assets/js/571.4321f994.js"><link rel="prefetch" href="/assets/js/572.8ab39750.js"><link rel="prefetch" href="/assets/js/573.e7b53730.js"><link rel="prefetch" href="/assets/js/574.637b580f.js"><link rel="prefetch" href="/assets/js/575.76b4f37b.js"><link rel="prefetch" href="/assets/js/576.f7e9268a.js"><link rel="prefetch" href="/assets/js/577.45296474.js"><link rel="prefetch" href="/assets/js/578.21525c52.js"><link rel="prefetch" href="/assets/js/579.0d0ccbb6.js"><link rel="prefetch" href="/assets/js/58.583ad48f.js"><link rel="prefetch" href="/assets/js/580.ae1d1ab5.js"><link rel="prefetch" href="/assets/js/581.f636f137.js"><link rel="prefetch" href="/assets/js/582.2feabe66.js"><link rel="prefetch" href="/assets/js/583.fb18929b.js"><link rel="prefetch" href="/assets/js/584.f79f539f.js"><link rel="prefetch" href="/assets/js/585.bf68105e.js"><link rel="prefetch" href="/assets/js/586.1d3cb142.js"><link rel="prefetch" href="/assets/js/587.f4bc14f0.js"><link rel="prefetch" href="/assets/js/588.e9be58d3.js"><link rel="prefetch" href="/assets/js/589.cf0068e8.js"><link rel="prefetch" href="/assets/js/59.609855d3.js"><link rel="prefetch" href="/assets/js/590.ac3b9f3f.js"><link rel="prefetch" href="/assets/js/591.61f4342c.js"><link rel="prefetch" href="/assets/js/592.c8b710ce.js"><link rel="prefetch" href="/assets/js/593.13bca0bd.js"><link rel="prefetch" href="/assets/js/594.49bc91f0.js"><link rel="prefetch" href="/assets/js/595.65755c43.js"><link rel="prefetch" href="/assets/js/596.85201e85.js"><link rel="prefetch" href="/assets/js/597.5968c2d2.js"><link rel="prefetch" href="/assets/js/598.cb10385e.js"><link rel="prefetch" href="/assets/js/599.329919fd.js"><link rel="prefetch" href="/assets/js/6.d05ff7d1.js"><link rel="prefetch" href="/assets/js/60.6192c5e6.js"><link rel="prefetch" href="/assets/js/600.6c4a484c.js"><link rel="prefetch" href="/assets/js/601.4461c2ae.js"><link rel="prefetch" href="/assets/js/602.a8d3fc33.js"><link rel="prefetch" href="/assets/js/603.ca2bb5fe.js"><link rel="prefetch" href="/assets/js/604.db803fb9.js"><link rel="prefetch" href="/assets/js/605.8ff2abfc.js"><link rel="prefetch" href="/assets/js/606.7113d146.js"><link rel="prefetch" href="/assets/js/607.f874afeb.js"><link rel="prefetch" href="/assets/js/608.69e0d555.js"><link rel="prefetch" href="/assets/js/609.e3e51762.js"><link rel="prefetch" href="/assets/js/61.11dbc940.js"><link rel="prefetch" href="/assets/js/610.48114a8b.js"><link rel="prefetch" href="/assets/js/611.20f5c8cd.js"><link rel="prefetch" href="/assets/js/612.49cf5c1f.js"><link rel="prefetch" href="/assets/js/613.c5d972ee.js"><link rel="prefetch" href="/assets/js/614.3712b906.js"><link rel="prefetch" href="/assets/js/615.0dfd0610.js"><link rel="prefetch" href="/assets/js/616.c60d74e0.js"><link rel="prefetch" href="/assets/js/617.05e47e1d.js"><link rel="prefetch" href="/assets/js/618.6f1c5ad5.js"><link rel="prefetch" href="/assets/js/619.6ab318a1.js"><link rel="prefetch" href="/assets/js/62.75354024.js"><link rel="prefetch" href="/assets/js/620.901c5159.js"><link rel="prefetch" href="/assets/js/621.add87549.js"><link rel="prefetch" href="/assets/js/622.408530c5.js"><link rel="prefetch" href="/assets/js/623.1aa20ea9.js"><link rel="prefetch" href="/assets/js/624.8616d341.js"><link rel="prefetch" href="/assets/js/625.7bdaa05f.js"><link rel="prefetch" href="/assets/js/626.6ca37760.js"><link rel="prefetch" href="/assets/js/627.1e67d181.js"><link rel="prefetch" href="/assets/js/628.69e16730.js"><link rel="prefetch" href="/assets/js/629.b7fbb50d.js"><link rel="prefetch" href="/assets/js/63.d3d8a2a7.js"><link rel="prefetch" href="/assets/js/630.a391b3de.js"><link rel="prefetch" href="/assets/js/631.f86fc53e.js"><link rel="prefetch" href="/assets/js/632.c1a60649.js"><link rel="prefetch" href="/assets/js/633.8ba0507c.js"><link rel="prefetch" href="/assets/js/634.549f3a14.js"><link rel="prefetch" href="/assets/js/635.c34e46b0.js"><link rel="prefetch" href="/assets/js/636.b9a9a30b.js"><link rel="prefetch" href="/assets/js/637.fac6e239.js"><link rel="prefetch" href="/assets/js/638.38c874bf.js"><link rel="prefetch" href="/assets/js/639.2cecf50a.js"><link rel="prefetch" href="/assets/js/64.fb01d06c.js"><link rel="prefetch" href="/assets/js/640.c9f97a1c.js"><link rel="prefetch" href="/assets/js/641.dc3dda81.js"><link rel="prefetch" href="/assets/js/642.b5923801.js"><link rel="prefetch" href="/assets/js/65.a5f22217.js"><link rel="prefetch" href="/assets/js/66.a48e0353.js"><link rel="prefetch" href="/assets/js/67.169d7837.js"><link rel="prefetch" href="/assets/js/68.27e92833.js"><link rel="prefetch" href="/assets/js/69.7643a0cf.js"><link rel="prefetch" href="/assets/js/7.63385f53.js"><link rel="prefetch" href="/assets/js/70.419bba25.js"><link rel="prefetch" href="/assets/js/71.ba04ac8a.js"><link rel="prefetch" href="/assets/js/72.6e7b692c.js"><link rel="prefetch" href="/assets/js/73.13285f8b.js"><link rel="prefetch" href="/assets/js/74.f87a5261.js"><link rel="prefetch" href="/assets/js/75.5e041d2a.js"><link rel="prefetch" href="/assets/js/76.f5339a14.js"><link rel="prefetch" href="/assets/js/77.d91c44df.js"><link rel="prefetch" href="/assets/js/78.29e9ac14.js"><link rel="prefetch" href="/assets/js/79.4b3118ff.js"><link rel="prefetch" href="/assets/js/8.901e16a3.js"><link rel="prefetch" href="/assets/js/80.8e295801.js"><link rel="prefetch" href="/assets/js/81.6d040b80.js"><link rel="prefetch" href="/assets/js/82.abf945e4.js"><link rel="prefetch" href="/assets/js/83.9bd95a69.js"><link rel="prefetch" href="/assets/js/84.bbc5db65.js"><link rel="prefetch" href="/assets/js/85.65463e7b.js"><link rel="prefetch" href="/assets/js/86.f64f6205.js"><link rel="prefetch" href="/assets/js/87.0260cfef.js"><link rel="prefetch" href="/assets/js/88.20d35720.js"><link rel="prefetch" href="/assets/js/89.87aaf95d.js"><link rel="prefetch" href="/assets/js/9.639ec32e.js"><link rel="prefetch" href="/assets/js/90.aca688c1.js"><link rel="prefetch" href="/assets/js/91.209eeece.js"><link rel="prefetch" href="/assets/js/92.6569647a.js"><link rel="prefetch" href="/assets/js/93.8b68023f.js"><link rel="prefetch" href="/assets/js/94.f32ead7e.js"><link rel="prefetch" href="/assets/js/95.953de281.js"><link rel="prefetch" href="/assets/js/96.3b33cb4c.js"><link rel="prefetch" href="/assets/js/97.f1ecb3a8.js"><link rel="prefetch" href="/assets/js/98.99874bfb.js"><link rel="prefetch" href="/assets/js/99.642326ea.js"><link rel="prefetch" href="/assets/js/vendors~docsearch.ac6383e3.js">
    <link rel="stylesheet" href="/assets/css/0.styles.f7fca28c.css">
  </head>
  <body>
    <div id="app" data-server-rendered="true"><div class="theme-container"><header class="navbar"><div class="sidebar-button"><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" role="img" viewBox="0 0 448 512" class="icon"><path fill="currentColor" d="M436 124H12c-6.627 0-12-5.373-12-12V80c0-6.627 5.373-12 12-12h424c6.627 0 12 5.373 12 12v32c0 6.627-5.373 12-12 12zm0 160H12c-6.627 0-12-5.373-12-12v-32c0-6.627 5.373-12 12-12h424c6.627 0 12 5.373 12 12v32c0 6.627-5.373 12-12 12zm0 160H12c-6.627 0-12-5.373-12-12v-32c0-6.627 5.373-12 12-12h424c6.627 0 12 5.373 12 12v32c0 6.627-5.373 12-12 12z"></path></svg></div> <a href="/zh/" class="home-link router-link-active"><img src="/img/logo.png" alt=" " class="logo"></a> <div class="links"><div class="search-box"><input aria-label="Search" autocomplete="off" spellcheck="false" value=""> <!----></div> <nav class="nav-links can-hide"><div class="nav-item"><div class="dropdown-wrapper"><a class="dropdown-title"><span class="title">文档</span> <span class="arrow right"></span></a> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/zh/UserGuide/Master/QuickStart/QuickStart.html" class="nav-link">In progress</a></li><li class="dropdown-item"><!----> <a href="/zh/UserGuide/V0.12.x/QuickStart/QuickStart.html" class="nav-link">V0.12.x</a></li><li class="dropdown-item"><!----> <a href="/zh/UserGuide/V0.11.x/Get Started/QuickStart.html" class="nav-link">V0.11.x</a></li><li class="dropdown-item"><!----> <a href="/zh/UserGuide/V0.10.x/Get Started/QuickStart.html" class="nav-link">V0.10.x</a></li><li class="dropdown-item"><!----> <a href="/zh/UserGuide/V0.9.x/0-Get Started/1-QuickStart.html" class="nav-link">V0.9.x</a></li><li class="dropdown-item"><!----> <a href="/zh/UserGuide/V0.8.x/0-Get Started/1-QuickStart.html" class="nav-link">V0.8.x</a></li></ul></div></div><div class="nav-item"><a href="/zh/SystemDesign/Architecture/Architecture.html" class="nav-link">系统设计</a></div><div class="nav-item"><a href="/zh/Download/" class="nav-link">下载</a></div><div class="nav-item"><div class="dropdown-wrapper"><a class="dropdown-title"><span class="title">社区</span> <span class="arrow right"></span></a> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="https://cwiki.apache.org/confluence/display/iotdb" class="nav-link external">
  Wiki
  <!----></a></li><li class="dropdown-item"><!----> <a href="/zh/Community/Community-Project Committers.html" class="nav-link">开发人员</a></li><li class="dropdown-item"><!----> <a href="/zh/Community/Community-Powered By.html" class="nav-link">技术支持</a></li><li class="dropdown-item"><!----> <a href="/Community/Materials.html" class="nav-link">活动与报告</a></li><li class="dropdown-item"><!----> <a href="/zh/Community/Feedback.html" class="nav-link">交流与反馈</a></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><a class="dropdown-title"><span class="title">开发</span> <span class="arrow right"></span></a> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/zh/Development/VoteRelease.html" class="nav-link">如何投票</a></li><li class="dropdown-item"><!----> <a href="/zh/Development/HowToCommit.html" class="nav-link">如何提交代码</a></li><li class="dropdown-item"><!----> <a href="/zh/Development/Committer.html" class="nav-link">成为Committer</a></li><li class="dropdown-item"><!----> <a href="/zh/Development/ContributeGuide.html" class="nav-link">项目开发指南</a></li><li class="dropdown-item"><!----> <a href="/zh/Development/format-changelist.html" class="nav-link">TsFile的更改列表</a></li><li class="dropdown-item"><!----> <a href="/zh/Development/rpc-changelist.html" class="nav-link">RPC变更清单</a></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><a class="dropdown-title"><span class="title">ASF</span> <span class="arrow right"></span></a> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="http://www.apache.org/" class="nav-link external">
  基金会
  <!----></a></li><li class="dropdown-item"><!----> <a href="http://www.apache.org/licenses/" class="nav-link external">
  许可证
  <!----></a></li><li class="dropdown-item"><!----> <a href="http://www.apache.org/security/" class="nav-link external">
  安全
  <!----></a></li><li class="dropdown-item"><!----> <a href="http://www.apache.org/foundation/sponsorship.html" class="nav-link external">
  赞助
  <!----></a></li><li class="dropdown-item"><!----> <a href="http://www.apache.org/foundation/thanks.html" class="nav-link external">
  致谢
  <!----></a></li><li class="dropdown-item"><!----> <a href="http://www.apache.org/events/current-event" class="nav-link external">
  活动
  <!----></a></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><a class="dropdown-title"><span class="title">语言</span> <span class="arrow right"></span></a> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/UserGuide/V0.12.x/IoTDB-SQL-Language/DML-Data-Manipulation-Language.html" class="nav-link">English</a></li><li class="dropdown-item"><!----> <a href="/zh/UserGuide/V0.12.x/IoTDB-SQL-Language/DML-Data-Manipulation-Language.html" aria-current="page" class="nav-link router-link-exact-active router-link-active">简体中文</a></li></ul></div></div> <a href="https://github.com/apache/iotdb.git" target="_blank" rel="noopener noreferrer" class="repo-link">
    gitHub
    <span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a></nav></div></header> <div class="sidebar-mask"></div> <aside class="sidebar"><nav class="nav-links"><div class="nav-item"><div class="dropdown-wrapper"><a class="dropdown-title"><span class="title">文档</span> <span class="arrow right"></span></a> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/zh/UserGuide/Master/QuickStart/QuickStart.html" class="nav-link">In progress</a></li><li class="dropdown-item"><!----> <a href="/zh/UserGuide/V0.12.x/QuickStart/QuickStart.html" class="nav-link">V0.12.x</a></li><li class="dropdown-item"><!----> <a href="/zh/UserGuide/V0.11.x/Get Started/QuickStart.html" class="nav-link">V0.11.x</a></li><li class="dropdown-item"><!----> <a href="/zh/UserGuide/V0.10.x/Get Started/QuickStart.html" class="nav-link">V0.10.x</a></li><li class="dropdown-item"><!----> <a href="/zh/UserGuide/V0.9.x/0-Get Started/1-QuickStart.html" class="nav-link">V0.9.x</a></li><li class="dropdown-item"><!----> <a href="/zh/UserGuide/V0.8.x/0-Get Started/1-QuickStart.html" class="nav-link">V0.8.x</a></li></ul></div></div><div class="nav-item"><a href="/zh/SystemDesign/Architecture/Architecture.html" class="nav-link">系统设计</a></div><div class="nav-item"><a href="/zh/Download/" class="nav-link">下载</a></div><div class="nav-item"><div class="dropdown-wrapper"><a class="dropdown-title"><span class="title">社区</span> <span class="arrow right"></span></a> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="https://cwiki.apache.org/confluence/display/iotdb" class="nav-link external">
  Wiki
  <!----></a></li><li class="dropdown-item"><!----> <a href="/zh/Community/Community-Project Committers.html" class="nav-link">开发人员</a></li><li class="dropdown-item"><!----> <a href="/zh/Community/Community-Powered By.html" class="nav-link">技术支持</a></li><li class="dropdown-item"><!----> <a href="/Community/Materials.html" class="nav-link">活动与报告</a></li><li class="dropdown-item"><!----> <a href="/zh/Community/Feedback.html" class="nav-link">交流与反馈</a></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><a class="dropdown-title"><span class="title">开发</span> <span class="arrow right"></span></a> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/zh/Development/VoteRelease.html" class="nav-link">如何投票</a></li><li class="dropdown-item"><!----> <a href="/zh/Development/HowToCommit.html" class="nav-link">如何提交代码</a></li><li class="dropdown-item"><!----> <a href="/zh/Development/Committer.html" class="nav-link">成为Committer</a></li><li class="dropdown-item"><!----> <a href="/zh/Development/ContributeGuide.html" class="nav-link">项目开发指南</a></li><li class="dropdown-item"><!----> <a href="/zh/Development/format-changelist.html" class="nav-link">TsFile的更改列表</a></li><li class="dropdown-item"><!----> <a href="/zh/Development/rpc-changelist.html" class="nav-link">RPC变更清单</a></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><a class="dropdown-title"><span class="title">ASF</span> <span class="arrow right"></span></a> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="http://www.apache.org/" class="nav-link external">
  基金会
  <!----></a></li><li class="dropdown-item"><!----> <a href="http://www.apache.org/licenses/" class="nav-link external">
  许可证
  <!----></a></li><li class="dropdown-item"><!----> <a href="http://www.apache.org/security/" class="nav-link external">
  安全
  <!----></a></li><li class="dropdown-item"><!----> <a href="http://www.apache.org/foundation/sponsorship.html" class="nav-link external">
  赞助
  <!----></a></li><li class="dropdown-item"><!----> <a href="http://www.apache.org/foundation/thanks.html" class="nav-link external">
  致谢
  <!----></a></li><li class="dropdown-item"><!----> <a href="http://www.apache.org/events/current-event" class="nav-link external">
  活动
  <!----></a></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><a class="dropdown-title"><span class="title">语言</span> <span class="arrow right"></span></a> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/UserGuide/V0.12.x/IoTDB-SQL-Language/DML-Data-Manipulation-Language.html" class="nav-link">English</a></li><li class="dropdown-item"><!----> <a href="/zh/UserGuide/V0.12.x/IoTDB-SQL-Language/DML-Data-Manipulation-Language.html" aria-current="page" class="nav-link router-link-exact-active router-link-active">简体中文</a></li></ul></div></div> <a href="https://github.com/apache/iotdb.git" target="_blank" rel="noopener noreferrer" class="repo-link">
    gitHub
    <span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a></nav>  <ul class="sidebar-links"><li><section class="sidebar-group depth-0"><p class="sidebar-heading"><span>IoTDB用户手册 (V0.12.x)</span> <!----></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>IoTDB简介</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>快速上手</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>数据模式与概念</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>SQL命令行终端(CLI)</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>权限管理</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading open"><span>IoTDB-SQL 语言</span> <span class="arrow down"></span></p> <ul class="sidebar-links sidebar-group-items"><li><a href="/zh/UserGuide/V0.12.x/IoTDB-SQL-Language/DDL-Data-Definition-Language.html" class="sidebar-link">数据定义语言（DDL）</a></li><li><a href="/zh/UserGuide/V0.12.x/IoTDB-SQL-Language/DML-Data-Manipulation-Language.html" aria-current="page" class="active sidebar-link">数据操作语言（DML）</a></li><li><a href="/zh/UserGuide/V0.12.x/IoTDB-SQL-Language/Maintenance-Command.html" class="sidebar-link">运维命令</a></li></ul></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>应用编程接口</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>用户定义函数(UDF)</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>通信服务协议</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>系统工具</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>端云协同</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>系统集成</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>集群搭建</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>常见问题</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>附录</span> <span class="arrow right"></span></p> <!----></section></li></ul> </aside> <main class="page"> <div class="content content__default"><h2 id="数据操作语言-dml"><a href="#数据操作语言-dml" class="header-anchor">#</a> 数据操作语言（DML）</h2> <h3 id="数据写入"><a href="#数据写入" class="header-anchor">#</a> 数据写入</h3> <p>IoTDB为用户提供多种插入实时数据的方式，例如在<a href="/zh/UserGuide/V0.12.x/CLI/Command-Line-Interface.html">Cli/Shell工具</a>中直接输入插入数据的INSERT语句，或使用Java API（标准<a href="/zh/UserGuide/V0.12.x/API/Programming-JDBC.html">Java JDBC</a>接口）单条或批量执行插入数据的INSERT语句。</p> <p>本节主要为您介绍实时数据接入的INSERT语句在场景中的实际使用示例，有关INSERT SQL语句的详细语法请参见本文<a href="/zh/UserGuide/V0.12.x/Appendix/SQL-Reference.html">INSERT语句</a>节。</p> <h4 id="使用insert语句"><a href="#使用insert语句" class="header-anchor">#</a> 使用INSERT语句</h4> <p>使用INSERT语句可以向指定的已经创建的一条或多条时间序列中插入数据。对于每一条数据，均由一个时间戳类型的时间戳和一个数值或布尔值、字符串类型的传感器采集值组成。</p> <p>在本节的场景实例下，以其中的两个时间序列<code>root.ln.wf02.wt02.status</code>和<code>root.ln.wf02.wt02.hardware</code>为例 ，它们的数据类型分别为BOOLEAN和TEXT。</p> <p>单列数据插入示例代码如下：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>IoTDB &gt; insert into root.ln.wf02.wt02(timestamp,status) values(1,true)
IoTDB &gt; insert into root.ln.wf02.wt02(timestamp,hardware) values(1, &quot;v1&quot;)
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br></div></div><p>以上示例代码将长整型的timestamp以及值为true的数据插入到时间序列<code>root.ln.wf02.wt02.status</code>中和将长整型的timestamp以及值为”v1”的数据插入到时间序列<code>root.ln.wf02.wt02.hardware</code>中。执行成功后会返回执行时间，代表数据插入已完成。</p> <blockquote><p>注意：在IoTDB中，TEXT类型的数据单双引号都可以来表示,上面的插入语句是用的是双引号表示TEXT类型数据，下面的示例将使用单引号表示TEXT类型数据。</p></blockquote> <p>INSERT语句还可以支持在同一个时间点下多列数据的插入，同时向2时间点插入上述两个时间序列的值，多列数据插入示例代码如下：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>IoTDB &gt; insert into root.ln.wf02.wt02(timestamp, status, hardware) VALUES (2, false, 'v2')
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>插入数据后我们可以使用SELECT语句简单查询已插入的数据。</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>IoTDB &gt; select * from root.ln.wf02 where time &lt; 3
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>结果如图所示。由查询结果可以看出，单列、多列数据的插入操作正确执行。</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+--------------------------+------------------------+
|                         Time|root.ln.wf02.wt02.hardware|root.ln.wf02.wt02.status|
+-----------------------------+--------------------------+------------------------+
|1970-01-01T08:00:00.001+08:00|                        v1|                    true|
|1970-01-01T08:00:00.002+08:00|                        v2|                   false|
+-----------------------------+--------------------------+------------------------+
Total line number = 2
It costs 0.170s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br></div></div><h3 id="数据查询"><a href="#数据查询" class="header-anchor">#</a> 数据查询</h3> <h4 id="时间条件过滤查询"><a href="#时间条件过滤查询" class="header-anchor">#</a> 时间条件过滤查询</h4> <p>本节主要介绍时间切片查询的相关示例，主要使用的是<a href="/zh/UserGuide/V0.12.x/Appendix/SQL-Reference.html">IoTDB SELECT语句</a>。同时，您也可以使用<a href="/zh/UserGuide/V0.12.x/API/Programming-JDBC.html">Java JDBC</a>标准接口来执行相关的查询语句。</p> <ul><li>根据一个时间区间选择一列数据</li></ul> <p>SQL语句为：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select temperature from root.ln.wf01.wt01 where time &lt; 2017-11-01T00:08:00.000
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>其含义为：</p> <p>被选择的设备为ln集团wf01子站wt01设备；被选择的时间序列为温度传感器（temperature）；该语句要求选择出该设备在“2017-11-01T00:08:00.000”（此处可以使用多种时间格式，详情可参看<a href="/zh/UserGuide/V0.12.x/Data-Concept/Data-Model-and-Terminology.html">2.1节</a>）时间点以前的所有温度传感器的值。</p> <p>该SQL语句的执行结果如下：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+-----------------------------+
|                         Time|root.ln.wf01.wt01.temperature|
+-----------------------------+-----------------------------+
|2017-11-01T00:00:00.000+08:00|                        25.96|
|2017-11-01T00:01:00.000+08:00|                        24.36|
|2017-11-01T00:02:00.000+08:00|                        20.09|
|2017-11-01T00:03:00.000+08:00|                        20.18|
|2017-11-01T00:04:00.000+08:00|                        21.13|
|2017-11-01T00:05:00.000+08:00|                        22.72|
|2017-11-01T00:06:00.000+08:00|                        20.71|
|2017-11-01T00:07:00.000+08:00|                        21.45|
+-----------------------------+-----------------------------+
Total line number = 8
It costs 0.026s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br></div></div><ul><li>根据一个时间区间选择多列数据</li></ul> <p>SQL语句为：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select status, temperature from root.ln.wf01.wt01 where time &gt; 2017-11-01T00:05:00.000 and time &lt; 2017-11-01T00:12:00.000;
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>其含义为：</p> <p>被选择的设备为ln集团wf01子站wt01设备；被选择的时间序列为供电状态（status）和温度传感器（temperature）；该语句要求选择出“2017-11-01T00:05:00.000”至“2017-11-01T00:12:00.000”之间的所选时间序列的值。</p> <p>该SQL语句的执行结果如下：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+------------------------+-----------------------------+
|                         Time|root.ln.wf01.wt01.status|root.ln.wf01.wt01.temperature|
+-----------------------------+------------------------+-----------------------------+
|2017-11-01T00:06:00.000+08:00|                   false|                        20.71|
|2017-11-01T00:07:00.000+08:00|                   false|                        21.45|
|2017-11-01T00:08:00.000+08:00|                   false|                        22.58|
|2017-11-01T00:09:00.000+08:00|                   false|                        20.98|
|2017-11-01T00:10:00.000+08:00|                    true|                        25.52|
|2017-11-01T00:11:00.000+08:00|                   false|                        22.91|
+-----------------------------+------------------------+-----------------------------+
Total line number = 6
It costs 0.018s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br></div></div><ul><li>按照多个时间区间选择同一设备的多列数据</li></ul> <p>IoTDB支持在一次查询中指定多个时间区间条件，用户可以根据需求随意组合时间区间条件。例如，</p> <p>SQL语句为：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select status,temperature from root.ln.wf01.wt01 where (time &gt; 2017-11-01T00:05:00.000 and time &lt; 2017-11-01T00:12:00.000) or (time &gt;= 2017-11-01T16:35:00.000 and time &lt;= 2017-11-01T16:37:00.000);
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>其含义为：</p> <p>被选择的设备为ln集团wf01子站wt01设备；被选择的时间序列为“供电状态（status）”和“温度传感器（temperature）”；该语句指定了两个不同的时间区间，分别为“2017-11-01T00:05:00.000至2017-11-01T00:12:00.000”和“2017-11-01T16:35:00.000至2017-11-01T16:37:00.000”；该语句要求选择出满足任一时间区间的被选时间序列的值。</p> <p>该SQL语句的执行结果如下：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+------------------------+-----------------------------+
|                         Time|root.ln.wf01.wt01.status|root.ln.wf01.wt01.temperature|
+-----------------------------+------------------------+-----------------------------+
|2017-11-01T00:06:00.000+08:00|                   false|                        20.71|
|2017-11-01T00:07:00.000+08:00|                   false|                        21.45|
|2017-11-01T00:08:00.000+08:00|                   false|                        22.58|
|2017-11-01T00:09:00.000+08:00|                   false|                        20.98|
|2017-11-01T00:10:00.000+08:00|                    true|                        25.52|
|2017-11-01T00:11:00.000+08:00|                   false|                        22.91|
|2017-11-01T16:35:00.000+08:00|                    true|                        23.44|
|2017-11-01T16:36:00.000+08:00|                   false|                        21.98|
|2017-11-01T16:37:00.000+08:00|                   false|                        21.93|
+-----------------------------+------------------------+-----------------------------+
Total line number = 9
It costs 0.018s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><ul><li>按照多个时间区间选择不同设备的多列数据</li></ul> <p>该系统支持在一次查询中选择任意列的数据，也就是说，被选择的列可以来源于不同的设备。例如，SQL语句为：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select wf01.wt01.status,wf02.wt02.hardware from root.ln where (time &gt; 2017-11-01T00:05:00.000 and time &lt; 2017-11-01T00:12:00.000) or (time &gt;= 2017-11-01T16:35:00.000 and time &lt;= 2017-11-01T16:37:00.000);
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>其含义为：</p> <p>被选择的时间序列为“ln集团wf01子站wt01设备的供电状态”以及“ln集团wf02子站wt02设备的硬件版本”；该语句指定了两个时间区间，分别为“2017-11-01T00:05:00.000至2017-11-01T00:12:00.000”和“2017-11-01T16:35:00.000至2017-11-01T16:37:00.000”；该语句要求选择出满足任意时间区间的被选时间序列的值。</p> <p>该SQL语句的执行结果如下：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+------------------------+--------------------------+
|                         Time|root.ln.wf01.wt01.status|root.ln.wf02.wt02.hardware|
+-----------------------------+------------------------+--------------------------+
|2017-11-01T00:06:00.000+08:00|                   false|                        v1|
|2017-11-01T00:07:00.000+08:00|                   false|                        v1|
|2017-11-01T00:08:00.000+08:00|                   false|                        v1|
|2017-11-01T00:09:00.000+08:00|                   false|                        v1|
|2017-11-01T00:10:00.000+08:00|                    true|                        v2|
|2017-11-01T00:11:00.000+08:00|                   false|                        v1|
|2017-11-01T16:35:00.000+08:00|                    true|                        v2|
|2017-11-01T16:36:00.000+08:00|                   false|                        v1|
|2017-11-01T16:37:00.000+08:00|                   false|                        v1|
+-----------------------------+------------------------+--------------------------+
Total line number = 9
It costs 0.014s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><h4 id="其他结果对齐方式"><a href="#其他结果对齐方式" class="header-anchor">#</a> 其他结果对齐方式</h4> <ul><li>根据时间降序返回
IoTDB 在 0.11 版本开始支持 'order by time' 语句, 用于对结果按照时间进行降序展示。例如，SQL语句为：</li></ul> <div class="language-sql line-numbers-mode"><pre class="language-sql"><code><span class="token keyword">select</span> <span class="token operator">*</span> <span class="token keyword">from</span> root<span class="token punctuation">.</span>ln <span class="token keyword">where</span> <span class="token keyword">time</span> <span class="token operator">&gt;</span> <span class="token number">1</span> <span class="token keyword">order</span> <span class="token keyword">by</span> <span class="token keyword">time</span> <span class="token keyword">desc</span> <span class="token keyword">limit</span> <span class="token number">10</span><span class="token punctuation">;</span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>语句执行的结果为：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+--------------------------+------------------------+-----------------------------+------------------------+
|                         Time|root.ln.wf02.wt02.hardware|root.ln.wf02.wt02.status|root.ln.wf01.wt01.temperature|root.ln.wf01.wt01.status|
+-----------------------------+--------------------------+------------------------+-----------------------------+------------------------+
|2017-11-07T23:59:00.000+08:00|                        v1|                   false|                        21.07|                   false|
|2017-11-07T23:58:00.000+08:00|                        v1|                   false|                        22.93|                   false|
|2017-11-07T23:57:00.000+08:00|                        v2|                    true|                        24.39|                    true|
|2017-11-07T23:56:00.000+08:00|                        v2|                    true|                        24.44|                    true|
|2017-11-07T23:55:00.000+08:00|                        v2|                    true|                         25.9|                    true|
|2017-11-07T23:54:00.000+08:00|                        v1|                   false|                        22.52|                   false|
|2017-11-07T23:53:00.000+08:00|                        v2|                    true|                        24.58|                    true|
|2017-11-07T23:52:00.000+08:00|                        v1|                   false|                        20.18|                   false|
|2017-11-07T23:51:00.000+08:00|                        v1|                   false|                        22.24|                   false|
|2017-11-07T23:50:00.000+08:00|                        v2|                    true|                         23.7|                    true|
+-----------------------------+--------------------------+------------------------+-----------------------------+------------------------+
Total line number = 10
It costs 0.016s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br></div></div><p>更多语法请参照 <a href="/zh/UserGuide/V0.12.x/Appendix/SQL-Reference.html">SQL REFERENCE</a>.</p> <ul><li>IoTDB支持另外两种结果返回形式: 按设备时间对齐 'align by device' 和 时序不对齐 'disable align'.</li></ul> <p>'align by device' 对齐方式下，设备ID会单独作为一列出现。在 select 子句中写了多少列，最终结果就会有该列数+2 （时间列和设备名字列）。SQL形如:</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select * from root.ln.* where time &lt;= 2017-11-01T00:01:00 align by device
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>结果如下：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+-----------------+-----------+------+--------+
|                         Time|           Device|temperature|status|hardware|
+-----------------------------+-----------------+-----------+------+--------+
|2017-11-01T00:00:00.000+08:00|root.ln.wf01.wt01|      25.96|  true|    null|
|2017-11-01T00:01:00.000+08:00|root.ln.wf01.wt01|      24.36|  true|    null|
|1970-01-01T08:00:00.001+08:00|root.ln.wf02.wt02|       null|  true|      v1|
|1970-01-01T08:00:00.002+08:00|root.ln.wf02.wt02|       null| false|      v2|
|2017-11-01T00:00:00.000+08:00|root.ln.wf02.wt02|       null|  true|      v2|
|2017-11-01T00:01:00.000+08:00|root.ln.wf02.wt02|       null|  true|      v2|
+-----------------------------+-----------------+-----------+------+--------+
Total line number = 6
It costs 0.012s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br></div></div><p>'disable align' 意味着每条时序就有 2 列存在。Disable Align只能用于查询语句句尾，不能用于聚合查询、Fill语句、Group by或Group by device语句，但可用于Limit语句。结果显示若无数据显示为空白。</p> <p>SQL形如:</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select * from root.ln.* where time &lt;= 2017-11-01T00:01:00 disable align
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>结果如下：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+--------------------------+-----------------------------+------------------------+-----------------------------+-----------------------------+-----------------------------+------------------------+
|                         Time|root.ln.wf02.wt02.hardware|                         Time|root.ln.wf02.wt02.status|                         Time|root.ln.wf01.wt01.temperature|                         Time|root.ln.wf01.wt01.status|
+-----------------------------+--------------------------+-----------------------------+------------------------+-----------------------------+-----------------------------+-----------------------------+------------------------+
|1970-01-01T08:00:00.001+08:00|                        v1|1970-01-01T08:00:00.001+08:00|                    true|2017-11-01T00:00:00.000+08:00|                        25.96|2017-11-01T00:00:00.000+08:00|                    true|
|1970-01-01T08:00:00.002+08:00|                        v2|1970-01-01T08:00:00.002+08:00|                   false|2017-11-01T00:01:00.000+08:00|                        24.36|2017-11-01T00:01:00.000+08:00|                    true|
|2017-11-01T00:00:00.000+08:00|                        v2|2017-11-01T00:00:00.000+08:00|                    true|                         null|                         null|                         null|                    null|
|2017-11-01T00:01:00.000+08:00|                        v2|2017-11-01T00:01:00.000+08:00|                    true|                         null|                         null|                         null|                    null|
+-----------------------------+--------------------------+-----------------------------+------------------------+-----------------------------+-----------------------------+-----------------------------+------------------------+
Total line number = 4
It costs 0.018s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br></div></div><p>更多语法请参照<a href="/zh/UserGuide/V0.12.x/Appendix/SQL-Reference.html">SQL REFERENCE</a>。</p> <h4 id="聚合函数"><a href="#聚合函数" class="header-anchor">#</a> 聚合函数</h4> <p>本章节主要介绍聚合查询的相关示例，
主要使用的是IoTDB SELECT语句的聚合查询函数。</p> <ul><li>统计总点数</li></ul> <div class="language- line-numbers-mode"><pre class="language-text"><code>select count(status) from root.ln.wf01.wt01;
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>结果：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-------------------------------+
|count(root.ln.wf01.wt01.status)|
+-------------------------------+
|                          10080|
+-------------------------------+
Total line number = 1
It costs 0.016s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br></div></div><h4 id="时间区间分组聚合"><a href="#时间区间分组聚合" class="header-anchor">#</a> 时间区间分组聚合</h4> <p>本章节主要介绍时间区间分组聚合查询的相关示例，
主要使用的是IoTDB SELECT语句的<a href="/zh/UserGuide/V0.12.x/Appendix/SQL-Reference.html">GROUP BY子句</a>，
该子句是IoTDB中用于根据用户给定划分条件对结果集进行划分，并对已划分的结果集进行聚合计算的语句。
IoTDB支持根据时间间隔和自定义的滑动步长（默认值与时间间隔相同，自定义的值必须大于等于时间间隔）对结果集进行划分，默认结果按照时间升序排列。
同时，您也可以使用Java JDBC标准接口来执行相关的查询语句。</p> <p>GROUP BY语句为用户提供三类指定参数：</p> <ul><li>参数1：时间轴显示时间窗参数</li> <li>参数2：划分时间轴的时间间隔参数（必须为正数）</li> <li>参数3：滑动步长（可选参数，默认值与时间间隔相同，自定义的值必须大于等于时间间隔）</li></ul> <p>三类参数的实际含义已经在下图中指出，这三类参数里，第三个参数是可选的。
接下来，我们将给出三种典型的降频聚合查询的例子：
滑动步长未指定，
指定滑动步长，
带值过滤条件。</p> <img src="https://user-images.githubusercontent.com/16079446/69109512-f808bc80-0ab2-11ea-9e4d-b2b2f58fb474.png" style="width:100%;max-width:800px;max-height:600px;margin-left:auto;margin-right:auto;display:block;"> <ul><li>未指定滑动步长的降频聚合查询</li></ul> <p>对应的SQL语句是:</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select count(status), max_value(temperature) from root.ln.wf01.wt01 group by ([2017-11-01T00:00:00, 2017-11-07T23:00:00),1d);
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>这条查询的含义是:</p> <p>由于用户没有指定滑动步长，滑动步长将会被默认设置为跟时间间隔参数相同，也就是<code>1d</code>。</p> <p>上面这个例子的第一个参数是显示窗口参数，决定了最终的显示范围是[2017-11-01T00:00:00, 2017-11-07T23:00:00)。</p> <p>上面这个例子的第二个参数是划分时间轴的时间间隔参数，将<code>1d</code>当作划分间隔，显示窗口参数的起始时间当作分割原点，时间轴即被划分为连续的时间间隔：[0,1d), [1d, 2d), [2d, 3d)等等。</p> <p>然后系统将会用WHERE子句中的时间和值过滤条件以及GROUP BY语句中的第一个参数作为数据的联合过滤条件，获得满足所有过滤条件的数据（在这个例子里是在[2017-11-01T00:00:00, 2017-11-07 T23:00:00)这个时间范围的数据），并把这些数据映射到之前分割好的时间轴中（这个例子里是从2017-11-01T00:00:00到2017-11-07T23:00:00:00的每一天）</p> <p>每个时间间隔窗口内都有数据，SQL执行后的结果集如下所示：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+-------------------------------+----------------------------------------+
|                         Time|count(root.ln.wf01.wt01.status)|max_value(root.ln.wf01.wt01.temperature)|
+-----------------------------+-------------------------------+----------------------------------------+
|2017-11-01T00:00:00.000+08:00|                           1440|                                    26.0|
|2017-11-02T00:00:00.000+08:00|                           1440|                                    26.0|
|2017-11-03T00:00:00.000+08:00|                           1440|                                   25.99|
|2017-11-04T00:00:00.000+08:00|                           1440|                                    26.0|
|2017-11-05T00:00:00.000+08:00|                           1440|                                    26.0|
|2017-11-06T00:00:00.000+08:00|                           1440|                                   25.99|
|2017-11-07T00:00:00.000+08:00|                           1380|                                    26.0|
+-----------------------------+-------------------------------+----------------------------------------+
Total line number = 7
It costs 0.024s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br></div></div><ul><li>指定滑动步长的时间区间分组聚合查询</li></ul> <p>对应的SQL语句是:</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select count(status), max_value(temperature) from root.ln.wf01.wt01 group by ([2017-11-01 00:00:00, 2017-11-07 23:00:00), 3h, 1d);
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>这条查询的含义是:</p> <p>由于用户指定了滑动步长为<code>1d</code>，GROUP BY语句执行时将会每次把时间间隔往后移动一天的步长，而不是默认的3小时。</p> <p>也就意味着，我们想要取从2017-11-01到2017-11-07每一天的凌晨0点到凌晨3点的数据。</p> <p>上面这个例子的第一个参数是显示窗口参数，决定了最终的显示范围是[2017-11-01T00:00:00, 2017-11-07T23:00:00)。</p> <p>上面这个例子的第二个参数是划分时间轴的时间间隔参数，将<code>3h</code>当作划分间隔，显示窗口参数的起始时间当作分割原点，时间轴即被划分为连续的时间间隔：[2017-11-01T00:00:00, 2017-11-01T03:00:00), [2017-11-02T00:00:00, 2017-11-02T03:00:00), [2017-11-03T00:00:00, 2017-11-03T03:00:00)等等。</p> <p>上面这个例子的第三个参数是每次时间间隔的滑动步长。</p> <p>然后系统将会用WHERE子句中的时间和值过滤条件以及GROUP BY语句中的第一个参数作为数据的联合过滤条件，获得满足所有过滤条件的数据（在这个例子里是在[2017-11-01T00:00:00, 2017-11-07 T23:00:00)这个时间范围的数据），并把这些数据映射到之前分割好的时间轴中（这个例子里是从2017-11-01T00:00:00到2017-11-07T23:00:00:00的每一天的凌晨0点到凌晨3点）</p> <p>每个时间间隔窗口内都有数据，SQL执行后的结果集如下所示：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+-------------------------------+----------------------------------------+
|                         Time|count(root.ln.wf01.wt01.status)|max_value(root.ln.wf01.wt01.temperature)|
+-----------------------------+-------------------------------+----------------------------------------+
|2017-11-01T00:00:00.000+08:00|                            180|                                   25.98|
|2017-11-02T00:00:00.000+08:00|                            180|                                   25.98|
|2017-11-03T00:00:00.000+08:00|                            180|                                   25.96|
|2017-11-04T00:00:00.000+08:00|                            180|                                   25.96|
|2017-11-05T00:00:00.000+08:00|                            180|                                    26.0|
|2017-11-06T00:00:00.000+08:00|                            180|                                   25.85|
|2017-11-07T00:00:00.000+08:00|                            180|                                   25.99|
+-----------------------------+-------------------------------+----------------------------------------+
Total line number = 7
It costs 0.006s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br></div></div><ul><li>按照自然月份的时间区间分组聚合查询</li></ul> <p>对应的SQL语句是:</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select count(status) from root.ln.wf01.wt01 where time &gt; 2017-11-01T01:00:00 group by([2017-11-01T00:00:00, 2019-11-07T23:00:00), 1mo, 2mo);
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>这条查询的含义是:</p> <p>由于用户指定了滑动步长为<code>2mo</code>，GROUP BY语句执行时将会每次把时间间隔往后移动2个自然月的步长，而不是默认的1个自然月。</p> <p>也就意味着，我们想要取从2017-11-01到2019-11-07每2个自然月的第一个月的数据。</p> <p>上面这个例子的第一个参数是显示窗口参数，决定了最终的显示范围是[2017-11-01T00:00:00, 2019-11-07T23:00:00)。</p> <p>起始时间为2017-11-01T00:00:00，滑动步长将会以起始时间作为标准按月递增，取当月的1号作为时间间隔的起始时间。</p> <p>上面这个例子的第二个参数是划分时间轴的时间间隔参数，将<code>1mo</code>当作划分间隔，显示窗口参数的起始时间当作分割原点，时间轴即被划分为连续的时间间隔：[2017-11-01T00:00:00, 2017-12-01T00:00:00), [2018-02-01T00:00:00, 2018-03-01T00:00:00), [2018-05-03T00:00:00, 2018-06-01T00:00:00)等等。</p> <p>上面这个例子的第三个参数是每次时间间隔的滑动步长。</p> <p>然后系统将会用WHERE子句中的时间和值过滤条件以及GROUP BY语句中的第一个参数作为数据的联合过滤条件，获得满足所有过滤条件的数据（在这个例子里是在[2017-11-01T00:00:00, 2019-11-07T23:00:00)这个时间范围的数据），并把这些数据映射到之前分割好的时间轴中（这个例子里是从2017-11-01T00:00:00到2019-11-07T23:00:00:00的每两个自然月的第一个月）</p> <p>每个时间间隔窗口内都有数据，SQL执行后的结果集如下所示：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+-------------------------------+
|                         Time|count(root.ln.wf01.wt01.status)|
+-----------------------------+-------------------------------+
|2017-11-01T00:00:00.000+08:00|                            259|
|2018-01-01T00:00:00.000+08:00|                            250|
|2018-03-01T00:00:00.000+08:00|                            259|
|2018-05-01T00:00:00.000+08:00|                            251|
|2018-07-01T00:00:00.000+08:00|                            242|
|2018-09-01T00:00:00.000+08:00|                            225|
|2018-11-01T00:00:00.000+08:00|                            216|
|2019-01-01T00:00:00.000+08:00|                            207|
|2019-03-01T00:00:00.000+08:00|                            216|
|2019-05-01T00:00:00.000+08:00|                            207|
|2019-07-01T00:00:00.000+08:00|                            199|
|2019-09-01T00:00:00.000+08:00|                            181|
|2019-11-01T00:00:00.000+08:00|                             60|
+-----------------------------+-------------------------------+
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br></div></div><p>对应的SQL语句是:</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select count(status) from root.ln.wf01.wt01 group by([2017-10-31T00:00:00, 2019-11-07T23:00:00), 1mo, 2mo);
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>这条查询的含义是:</p> <p>由于用户指定了滑动步长为<code>2mo</code>，GROUP BY语句执行时将会每次把时间间隔往后移动2个自然月的步长，而不是默认的1个自然月。</p> <p>也就意味着，我们想要取从2017-10-31到2019-11-07每2个自然月的第一个月的数据。</p> <p>与上述示例不同的是起始时间为2017-10-31T00:00:00，滑动步长将会以起始时间作为标准按月递增，取当月的31号（即最后一天）作为时间间隔的起始时间。若起始时间设置为30号，滑动步长会将时间间隔的起始时间设置为当月30号，若不存在则为最后一天。</p> <p>上面这个例子的第一个参数是显示窗口参数，决定了最终的显示范围是[2017-10-31T00:00:00, 2019-11-07T23:00:00)。</p> <p>上面这个例子的第二个参数是划分时间轴的时间间隔参数，将<code>1mo</code>当作划分间隔，显示窗口参数的起始时间当作分割原点，时间轴即被划分为连续的时间间隔：[2017-10-31T00:00:00, 2017-11-31T00:00:00), [2018-02-31T00:00:00, 2018-03-31T00:00:00), [2018-05-31T00:00:00, 2018-06-31T00:00:00)等等。</p> <p>上面这个例子的第三个参数是每次时间间隔的滑动步长。</p> <p>然后系统将会用WHERE子句中的时间和值过滤条件以及GROUP BY语句中的第一个参数作为数据的联合过滤条件，获得满足所有过滤条件的数据（在这个例子里是在[2017-10-31T00:00:00, 2019-11-07T23:00:00)这个时间范围的数据），并把这些数据映射到之前分割好的时间轴中（这个例子里是从2017-10-31T00:00:00到2019-11-07T23:00:00:00的每两个自然月的第一个月）</p> <p>每个时间间隔窗口内都有数据，SQL执行后的结果集如下所示：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+-------------------------------+
|                         Time|count(root.ln.wf01.wt01.status)|
+-----------------------------+-------------------------------+
|2017-10-31T00:00:00.000+08:00|                            251|
|2017-12-31T00:00:00.000+08:00|                            250|
|2018-02-28T00:00:00.000+08:00|                            259|
|2018-04-30T00:00:00.000+08:00|                            250|
|2018-06-30T00:00:00.000+08:00|                            242|
|2018-08-31T00:00:00.000+08:00|                            225|
|2018-10-31T00:00:00.000+08:00|                            216|
|2018-12-31T00:00:00.000+08:00|                            208|
|2019-02-28T00:00:00.000+08:00|                            216|
|2019-04-30T00:00:00.000+08:00|                            208|
|2019-06-30T00:00:00.000+08:00|                            199|
|2019-08-31T00:00:00.000+08:00|                            181|
|2019-10-31T00:00:00.000+08:00|                             69|
+-----------------------------+-------------------------------+
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br></div></div><ul><li>左开右闭区间</li></ul> <p>每个区间的结果时间戳为区间右端点，对应的SQL语句是:</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select count(status) from root.ln.wf01.wt01 group by ((2017-11-01T00:00:00, 2017-11-07T23:00:00],1d);
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>这条查询语句的时间区间是左开右闭的，结果中不会包含时间点2017-11-01的数据，但是会包含时间点2017-11-07的数据。</p> <p>SQL执行后的结果集如下所示：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+-------------------------------+
|                         Time|count(root.ln.wf01.wt01.status)|
+-----------------------------+-------------------------------+
|2017-11-02T00:00:00.000+08:00|                           1440|
|2017-11-03T00:00:00.000+08:00|                           1440|
|2017-11-04T00:00:00.000+08:00|                           1440|
|2017-11-05T00:00:00.000+08:00|                           1440|
|2017-11-06T00:00:00.000+08:00|                           1440|
|2017-11-07T00:00:00.000+08:00|                           1440|
|2017-11-07T23:00:00.000+08:00|                           1380|
+-----------------------------+-------------------------------+
Total line number = 7
It costs 0.004s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br></div></div><h4 id="路径层级分组聚合"><a href="#路径层级分组聚合" class="header-anchor">#</a> 路径层级分组聚合</h4> <p>在时间序列层级结构中，分层聚合查询用于对某一层级进行聚合查询。
这里使用LEVEL来统计指定层级下的聚合范围，该语句约定root为第0层序列，若统计&quot;root.ln&quot;下所有序列则需指定level为1。</p> <p>例如：在&quot;root.ln.wf01&quot;下存在多个子序列：wt01，wt02，wt03等均有名为status的序列，
如果需要统计这些子序列的status包含的点个数，使用以下查询:</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select count(status) from root.ln.wf01.* group by level=2
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>运行结果为：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+----------------------------+
|count(root.ln.wf01.*.status)|
+----------------------------+
|                       10080|
+----------------------------+
Total line number = 1
It costs 0.003s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br></div></div><p>假设此时添加两条序列，&quot;root.ln.wf01.wt01.temperature&quot; and &quot;root.ln.wf02.wt01.temperature&quot;。
需要同时查询&quot;root.ln.*.*.temperature&quot;在第二层级的count聚合结果和sum聚合结果，可以使用下列查询语句：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select count(temperature), sum(temperature) from root.ln.*.* group by level=2
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>运行结果：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+---------------------------------+---------------------------------+-------------------------------+-------------------------------+
|count(root.ln.wf02.*.temperature)|count(root.ln.wf01.*.temperature)|sum(root.ln.wf02.*.temperature)|sum(root.ln.wf01.*.temperature)|
+---------------------------------+---------------------------------+-------------------------------+-------------------------------+
|                                8|                                4|                          228.0|              91.83000183105469|
+---------------------------------+---------------------------------+-------------------------------+-------------------------------+
Total line number = 1
It costs 0.013s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br></div></div><p>若统计&quot;root.ln.*.*&quot;下第一层级的count聚合结果和sum聚合结果，则设置level=1即可:</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select count(temperature), sum(temperature) from root.ln.*.* group by level=1
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>运行结果：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+------------------------------+----------------------------+
|count(root.ln.*.*.temperature)|sum(root.ln.*.*.temperature)|
+------------------------------+----------------------------+
|                            12|           319.8300018310547|
+------------------------------+----------------------------+
Total line number = 1
It costs 0.013s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br></div></div><p>分层聚合查询也可被用于其他聚合函数，当前所支持的聚合函数为：count, sum, avg, last_value, first_value, min_time, max_time, min_value, max_value</p> <p>对于sum, avg, min_value, max_value四种聚合函数，需保证所有聚合的时间序列数据类型相同。其他聚合函数没有此限制。</p> <h4 id="时间区间和路径层级分组聚合查询"><a href="#时间区间和路径层级分组聚合查询" class="header-anchor">#</a> 时间区间和路径层级分组聚合查询</h4> <p>除此之外，还可以通过定义LEVEL来统计指定层级下的数据点个数。</p> <p>例如：</p> <p>统计降采样后的数据点个数</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select count(status) from root.ln.wf01.wt01 group by ((2017-11-01T00:00:00, 2017-11-07T23:00:00],1d), level=1;
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>结果：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+-------------------------+
|                         Time|COUNT(root.ln.*.*.status)|
+-----------------------------+-------------------------+
|2017-11-02T00:00:00.000+08:00|                     1440|
|2017-11-03T00:00:00.000+08:00|                     1440|
|2017-11-04T00:00:00.000+08:00|                     1440|
|2017-11-05T00:00:00.000+08:00|                     1440|
|2017-11-06T00:00:00.000+08:00|                     1440|
|2017-11-07T00:00:00.000+08:00|                     1440|
|2017-11-07T23:00:00.000+08:00|                     1380|
+-----------------------------+-------------------------+
Total line number = 7
It costs 0.006s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br></div></div><p>加上滑动Step的降采样后的结果也可以汇总</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select count(status) from root.ln.wf01.wt01 group by ([0,20),2ms,3ms), level=1;
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+-------------------------+
|                         Time|COUNT(root.ln.*.*.status)|
+-----------------------------+-------------------------+
|2017-11-01T00:00:00.000+08:00|                      180|
|2017-11-02T00:00:00.000+08:00|                      180|
|2017-11-03T00:00:00.000+08:00|                      180|
|2017-11-04T00:00:00.000+08:00|                      180|
|2017-11-05T00:00:00.000+08:00|                      180|
|2017-11-06T00:00:00.000+08:00|                      180|
|2017-11-07T00:00:00.000+08:00|                      180|
+-----------------------------+-------------------------+
Total line number = 7
It costs 0.004s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br></div></div><h4 id="最新点查询"><a href="#最新点查询" class="header-anchor">#</a> 最新点查询</h4> <p>SQL语法：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select last &lt;Path&gt; [COMMA &lt;Path&gt;]* from &lt; PrefixPath &gt; [COMMA &lt; PrefixPath &gt;]* &lt;WhereClause&gt;
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>其含义是：查询时间序列prefixPath.path中最近时间戳的数据</p> <p>&lt;WhereClause&gt;中当前只支持含有'&gt;'或'&gt;='的时间过滤条件，任何其他过滤条件都将会返回异常。</p> <p>结果集为三列的结构</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+----+----------+-----+
|Time|timeseries|value|
+----+----------+-----+
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br></div></div><p>示例 1：查询 root.ln.wf01.wt01.status 的最新数据点</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>IoTDB&gt; select last status from root.ln.wf01.wt01
+-----------------------------+------------------------+-----+
|                         Time|              timeseries|value|
+-----------------------------+------------------------+-----+
|2017-11-07T23:59:00.000+08:00|root.ln.wf01.wt01.status|false|
+-----------------------------+------------------------+-----+
Total line number = 1
It costs 0.000s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br></div></div><p>示例 2：查询 root.ln.wf01.wt01 下 status，temperature 时间戳大于等于2017-11-07T23:50:00的最新数据点。</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>IoTDB&gt; select last status, temperature from root.ln.wf01.wt01 where time &gt;= 2017-11-07T23:50:00
+-----------------------------+-----------------------------+---------+
|                         Time|                   timeseries|    value|
+-----------------------------+-----------------------------+---------+
|2017-11-07T23:59:00.000+08:00|     root.ln.wf01.wt01.status|    false|
|2017-11-07T23:59:00.000+08:00|root.ln.wf01.wt01.temperature|21.067368|
+-----------------------------+-----------------------------+---------+
Total line number = 2
It costs 0.002s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br></div></div><h4 id="空值填充"><a href="#空值填充" class="header-anchor">#</a> 空值填充</h4> <p>在IoTDB的实际使用中，当进行时间序列的查询操作时，可能会出现在某些时间点值为null的情况，这会妨碍用户进行进一步的分析。 为了更好地反映数据更改的程度，用户希望可以自动填充缺失值。 因此，IoTDB系统引入了自动填充功能。</p> <p>自动填充功能是指对单列或多列执行时间序列查询时，根据用户指定的方法和有效时间范围填充空值。 如果查询点的值不为null，则填充功能将不起作用。</p> <blockquote><p>注意：在当前版本中，IoTDB为用户提供两种方法：Previous 和Linear。 Previous 方法用前一个值填充空白。 Linear方法通过线性拟合来填充空白。 并且填充功能只能在执行时间点查询时使用。</p></blockquote> <ul><li>填充功能</li></ul> <ul><li>Previous功能</li></ul> <p>当查询的时间戳值为空时，将使用前一个时间戳的值来填充空白。 形式化的先前方法如下（有关详细语法，请参见第7.1.3.6节）：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select &lt;path&gt; from &lt;prefixPath&gt; where time = &lt;T&gt; fill(&lt;data_type&gt;[previous, &lt;before_range&gt;], …)
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>表3-4给出了所有参数的详细说明。</p> <center>**表3-4previous填充参数列表**
<table><thead><tr><th style="text-align:left;">参数名称（不区分大小写）</th> <th style="text-align:left;">解释</th></tr></thead> <tbody><tr><td style="text-align:left;">path, prefixPath</td> <td style="text-align:left;">查询路径； 必填项</td></tr> <tr><td style="text-align:left;">T</td> <td style="text-align:left;">查询时间戳（只能指定一个）； 必填项</td></tr> <tr><td style="text-align:left;">data_type</td> <td style="text-align:left;">填充方法使用的数据类型。 可选值是int32，int64，float，double，boolean，text; 可选字段</td></tr> <tr><td style="text-align:left;">before_range</td> <td style="text-align:left;">表示前一种方法的有效时间范围。 当[T-before \ _range，T]范围内的值存在时，前一种方法将起作用。 如果未指定before_range，则before_range会使用默认值default_fill_interval; -1表示无穷大； 可选字段</td></tr></tbody></table></center> <p>在这里，我们举一个使用先前方法填充空值的示例。 SQL语句如下：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select temperature from root.sgcc.wf03.wt01 where time = 2017-11-01T16:37:50.000 fill(float[previous, 1m]) 
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>意思是：</p> <p>由于时间根目录root.sgcc.wf03.wt01.temperature在2017-11-01T16：37：50.000为空，因此系统使用以前的时间戳2017-11-01T16：37：00.000（且时间戳位于[2017-11-01T16:36:50.000, 2017-11-01T16:37:50.000]范围）进行填充和显示。</p> <p>在<a href="https://github.com/thulab/iotdb/files/4438687/OtherMaterial-Sample.Data.txt" target="_blank" rel="noopener noreferrer">样例数据中<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a>, 该语句的执行结果如下所示：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+-------------------------------+
|                         Time|root.sgcc.wf03.wt01.temperature|
+-----------------------------+-------------------------------+
|2017-11-01T16:37:50.000+08:00|                          21.93|
+-----------------------------+-------------------------------+
Total line number = 1
It costs 0.016s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br></div></div><p>值得注意的是，如果在指定的有效时间范围内没有值，系统将不会填充空值，如下所示：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>IoTDB&gt; select temperature from root.sgcc.wf03.wt01 where time = 2017-11-01T16:37:50.000 fill(float[previous, 1s]) 
+-----------------------------+-------------------------------+
|                         Time|root.sgcc.wf03.wt01.temperature|
+-----------------------------+-------------------------------+
|2017-11-01T16:37:50.000+08:00|                           null|
+-----------------------------+-------------------------------+
Total line number = 1
It costs 0.004s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br></div></div><ul><li>Linear方法</li></ul> <p>当查询的时间戳值为空时，将使用前一个和下一个时间戳的值来填充空白。 形式化线性方法如下：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select &lt;path&gt; from &lt;prefixPath&gt; where time = &lt;T&gt; fill(&lt;data_type&gt;[linear, &lt;before_range&gt;, &lt;after_range&gt;]…)
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>表3-5中给出了所有参数的详细说明。</p> <center>**表3-5线性填充参数列表**
<table><thead><tr><th style="text-align:left;">参数名称（不区分大小写）</th> <th style="text-align:left;">解释</th></tr></thead> <tbody><tr><td style="text-align:left;">path, prefixPath</td> <td style="text-align:left;">查询路径； 必填项</td></tr> <tr><td style="text-align:left;">T</td> <td style="text-align:left;">查询时间戳（只能指定一个）； 必填项</td></tr> <tr><td style="text-align:left;">data_type</td> <td style="text-align:left;">填充方法使用的数据类型。 可选值是int32，int64，float，double，boolean，text; 可选字段</td></tr> <tr><td style="text-align:left;">before_range, after_range</td> <td style="text-align:left;">表示线性方法的有效时间范围。 当[T-before_range，T + after_range]范围内的值存在时，前一种方法将起作用。 如果未明确指定before_range和after_range，则使用default_fill_interval。 -1表示无穷大； 可选字段</td></tr></tbody></table></center> <p>需要注意的是一旦时间序列在查询时间戳T时刻存在有效值，线性填充就回使用这个值作为结果返回。
除此之外，如果在[T-before_range，T]或[T, T + after_range]两个范围中任意一个范围内不存在有效填充值，则线性填充返回null值。</p> <p>在这里，我们举一个使用线性方法填充空值的示例。 SQL语句如下：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select temperature from root.sgcc.wf03.wt01 where time = 2017-11-01T16:37:50.000 fill(float [linear, 1m, 1m])
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>意思是：</p> <p>由于时间根目录root.sgcc.wf03.wt01.temperature在2017-11-01T16：37：50.000为空，因此系统使用以前的时间戳2017-11-01T16：37：00.000（且时间戳位于[2017- 11-01T16：36：50.000，2017-11-01T16：37：50.000]时间范围）及其值21.927326，下一个时间戳记2017-11-01T16：38：00.000（且时间戳记位于[2017-11-11] 01T16：37：50.000、2017-11-01T16：38：50.000]时间范围）及其值25.311783以执行线性拟合计算：</p> <p>21.927326 +（25.311783-21.927326）/ 60s * 50s = 24.747707</p> <p>在 <a href="https://github.com/thulab/iotdb/files/4438687/OtherMaterial-Sample.Data.txt" target="_blank" rel="noopener noreferrer">样例数据<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a>, 该语句的执行结果如下所示：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+-------------------------------+
|                         Time|root.sgcc.wf03.wt01.temperature|
+-----------------------------+-------------------------------+
|2017-11-01T16:37:50.000+08:00|                      24.746666|
+-----------------------------+-------------------------------+
Total line number = 1
It costs 0.017s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br></div></div><p>数据类型和填充方法之间的对应关系</p> <p>数据类型和支持的填充方法如表3-6所示。</p> <center>**表3-6数据类型和支持的填充方法**
<table><thead><tr><th style="text-align:left;">数据类型</th> <th style="text-align:left;">支持的填充方法</th></tr></thead> <tbody><tr><td style="text-align:left;">boolean</td> <td style="text-align:left;">previous</td></tr> <tr><td style="text-align:left;">int32</td> <td style="text-align:left;">previous, linear</td></tr> <tr><td style="text-align:left;">int64</td> <td style="text-align:left;">previous, linear</td></tr> <tr><td style="text-align:left;">float</td> <td style="text-align:left;">previous, linear</td></tr> <tr><td style="text-align:left;">double</td> <td style="text-align:left;">previous, linear</td></tr> <tr><td style="text-align:left;">text</td> <td style="text-align:left;">previous</td></tr></tbody></table></center> <blockquote><p>注意：应在Fill语句中至少指定一种填充方法。</p></blockquote> <ul><li>时间区间分组聚合查询补空值</li></ul> <p>时间区间分组聚合出的各个时间段的结果，支持使用前值补空。</p> <p>不允许设置滑动步长，默认为聚合时间区间，实际为定长采样。现在只支持 last_value 聚合函数。</p> <p>目前不支持线性插值补空值。</p> <p>PREVIOUS 和 PREVIOUSUNTILLAST 的区别</p> <ul><li>PREVIOUS：只要空值前边有值，就会用其填充空值。</li> <li>PREVIOUSUNTILLAST：不会填充此序列最新点后的空值</li></ul> <p>首先我们检查一下root.ln.wf01.wt01.temperature在时间2017-11-07T23:50:00以后的值</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>IoTDB&gt; SELECT temperature FROM root.ln.wf01.wt01 where time &gt;= 2017-11-07T23:50:00
+-----------------------------+-----------------------------+
|                         Time|root.ln.wf01.wt01.temperature|
+-----------------------------+-----------------------------+
|2017-11-07T23:50:00.000+08:00|                         23.7|
|2017-11-07T23:51:00.000+08:00|                        22.24|
|2017-11-07T23:52:00.000+08:00|                        20.18|
|2017-11-07T23:53:00.000+08:00|                        24.58|
|2017-11-07T23:54:00.000+08:00|                        22.52|
|2017-11-07T23:55:00.000+08:00|                         25.9|
|2017-11-07T23:56:00.000+08:00|                        24.44|
|2017-11-07T23:57:00.000+08:00|                        24.39|
|2017-11-07T23:58:00.000+08:00|                        22.93|
|2017-11-07T23:59:00.000+08:00|                        21.07|
+-----------------------------+-----------------------------+
Total line number = 10
It costs 0.002s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br></div></div><p>我们发现root.ln.wf01.wt01.temperature的最后时间和值是2017-11-07T23:59:00和21.07。</p> <p>SQL 示例:</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>SELECT last_value(temperature) FROM root.ln.wf01.wt01 GROUP BY([2017-11-07T23:50:00, 2017-11-08T00:01:00),1m) FILL (float[PREVIOUSUNTILLAST]);
SELECT last_value(temperature) FROM root.ln.wf01.wt01 GROUP BY([2017-11-07T23:50:00, 2017-11-08T00:01:00),1m) FILL (float[PREVIOUS]);
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br></div></div><p>结果：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+-----------------------------------------+
|                         Time|last_value(root.ln.wf01.wt01.temperature)|
+-----------------------------+-----------------------------------------+
|2017-11-07T23:50:00.000+08:00|                                     23.7|
|2017-11-07T23:51:00.000+08:00|                                    22.24|
|2017-11-07T23:52:00.000+08:00|                                    20.18|
|2017-11-07T23:53:00.000+08:00|                                    24.58|
|2017-11-07T23:54:00.000+08:00|                                    22.52|
|2017-11-07T23:55:00.000+08:00|                                     25.9|
|2017-11-07T23:56:00.000+08:00|                                    24.44|
|2017-11-07T23:57:00.000+08:00|                                    24.39|
|2017-11-07T23:58:00.000+08:00|                                    22.93|
|2017-11-07T23:59:00.000+08:00|                                    21.07|
|2017-11-08T00:00:00.000+08:00|                                     null|
+-----------------------------+-----------------------------------------+
Total line number = 11
It costs 0.005s

+-----------------------------+-----------------------------------------+
|                         Time|last_value(root.ln.wf01.wt01.temperature)|
+-----------------------------+-----------------------------------------+
|2017-11-07T23:50:00.000+08:00|                                     23.7|
|2017-11-07T23:51:00.000+08:00|                                    22.24|
|2017-11-07T23:52:00.000+08:00|                                    20.18|
|2017-11-07T23:53:00.000+08:00|                                    24.58|
|2017-11-07T23:54:00.000+08:00|                                    22.52|
|2017-11-07T23:55:00.000+08:00|                                     25.9|
|2017-11-07T23:56:00.000+08:00|                                    24.44|
|2017-11-07T23:57:00.000+08:00|                                    24.39|
|2017-11-07T23:58:00.000+08:00|                                    22.93|
|2017-11-07T23:59:00.000+08:00|                                    21.07|
|2017-11-08T00:00:00.000+08:00|                                    21.07|
+-----------------------------+-----------------------------------------+
Total line number = 11
It costs 0.006s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br><span class="line-number">33</span><br><span class="line-number">34</span><br><span class="line-number">35</span><br></div></div><p>解释:</p> <p>使用 PREVIOUSUNTILLAST 将不会填充2017-11-07T23:59:00以后的值。</p> <h4 id="limit-offset"><a href="#limit-offset" class="header-anchor">#</a> LIMIT &amp; OFFSET</h4> <p>IoTDB提供 <a href="/zh/UserGuide/V0.12.x/Appendix/SQL-Reference.html">LIMIT/SLIMIT</a> 子句和 <a href="/zh/UserGuide/V0.12.x/Appendix/SQL-Reference.html">OFFSET/SOFFSET</a> 子句，以使用户可以更好地控制查询结果。使用LIMIT和SLIMIT子句可让用户控制查询结果的行数和列数，
并且使用OFFSET和SOFSET子句允许用户设置结果显示的起始位置。</p> <p>请注意，按组查询不支持LIMIT和OFFSET。</p> <p>本章主要介绍查询结果的行和列控制的相关示例。你还可以使用 <a href="/zh/UserGuide/V0.12.x/API/Programming-JDBC.html">Java JDBC</a> 标准接口执行查询。</p> <ul><li>查询结果的行控制</li></ul> <p>通过使用LIMIT和OFFSET子句，用户可以以与行相关的方式控制查询结果。 我们将通过以下示例演示如何使用LIMIT和OFFSET子句。</p> <ul><li>示例1：基本的LIMIT子句</li></ul> <p>SQL语句是：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select status, temperature from root.ln.wf01.wt01 limit 10
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>意思是：</p> <p>所选设备为ln组wf01工厂wt01设备； 选择的时间序列是“状态”和“温度”。 SQL语句要求返回查询结果的前10行。</p> <p>结果如下所示：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+------------------------+-----------------------------+
|                         Time|root.ln.wf01.wt01.status|root.ln.wf01.wt01.temperature|
+-----------------------------+------------------------+-----------------------------+
|2017-11-01T00:00:00.000+08:00|                    true|                        25.96|
|2017-11-01T00:01:00.000+08:00|                    true|                        24.36|
|2017-11-01T00:02:00.000+08:00|                   false|                        20.09|
|2017-11-01T00:03:00.000+08:00|                   false|                        20.18|
|2017-11-01T00:04:00.000+08:00|                   false|                        21.13|
|2017-11-01T00:05:00.000+08:00|                   false|                        22.72|
|2017-11-01T00:06:00.000+08:00|                   false|                        20.71|
|2017-11-01T00:07:00.000+08:00|                   false|                        21.45|
|2017-11-01T00:08:00.000+08:00|                   false|                        22.58|
|2017-11-01T00:09:00.000+08:00|                   false|                        20.98|
+-----------------------------+------------------------+-----------------------------+
Total line number = 10
It costs 0.000s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br></div></div><ul><li>示例2：带OFFSET的LIMIT子句</li></ul> <p>SQL语句是：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select status, temperature from root.ln.wf01.wt01 limit 5 offset 3
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>意思是：</p> <p>所选设备为ln组wf01工厂wt01设备； 选择的时间序列是“状态”和“温度”。 SQL语句要求返回查询结果的第3至7行（第一行编号为0行）。</p> <p>结果如下所示：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+------------------------+-----------------------------+
|                         Time|root.ln.wf01.wt01.status|root.ln.wf01.wt01.temperature|
+-----------------------------+------------------------+-----------------------------+
|2017-11-01T00:03:00.000+08:00|                   false|                        20.18|
|2017-11-01T00:04:00.000+08:00|                   false|                        21.13|
|2017-11-01T00:05:00.000+08:00|                   false|                        22.72|
|2017-11-01T00:06:00.000+08:00|                   false|                        20.71|
|2017-11-01T00:07:00.000+08:00|                   false|                        21.45|
+-----------------------------+------------------------+-----------------------------+
Total line number = 5
It costs 0.342s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><ul><li>示例3：LIMIT子句与WHERE子句结合</li></ul> <p>SQL语句是：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select status,temperature from root.ln.wf01.wt01 where time &gt; 2017-11-01T00:05:00.000 and time&lt; 2017-11-01T00:12:00.000 limit 5 offset 3
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>意思是：</p> <p>所选设备为ln组wf01工厂wt01设备； 选择的时间序列是“状态”和“温度”。 SQL语句要求返回时间“ 2017-11-01T00：05：00.000”和“ 2017-11-01T00：12：00.000”之间的状态和温度传感器值的第3至4行（第一行） 编号为第0行）。</p> <p>结果如下所示：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+------------------------+-----------------------------+
|                         Time|root.ln.wf01.wt01.status|root.ln.wf01.wt01.temperature|
+-----------------------------+------------------------+-----------------------------+
|2017-11-01T00:03:00.000+08:00|                   false|                        20.18|
|2017-11-01T00:04:00.000+08:00|                   false|                        21.13|
|2017-11-01T00:05:00.000+08:00|                   false|                        22.72|
|2017-11-01T00:06:00.000+08:00|                   false|                        20.71|
|2017-11-01T00:07:00.000+08:00|                   false|                        21.45|
+-----------------------------+------------------------+-----------------------------+
Total line number = 5
It costs 0.000s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><ul><li>示例4：LIMIT子句与GROUP BY子句组合</li></ul> <p>SQL语句是：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select count(status), max_value(temperature) from root.ln.wf01.wt01 group by ([2017-11-01T00:00:00, 2017-11-07T23:00:00),1d) limit 4 offset 3
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>意思是：</p> <p>SQL语句子句要求返回查询结果的第3至6行（第一行编号为0行）。</p> <p>结果如下所示：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+-------------------------------+----------------------------------------+
|                         Time|count(root.ln.wf01.wt01.status)|max_value(root.ln.wf01.wt01.temperature)|
+-----------------------------+-------------------------------+----------------------------------------+
|2017-11-04T00:00:00.000+08:00|                           1440|                                    26.0|
|2017-11-05T00:00:00.000+08:00|                           1440|                                    26.0|
|2017-11-06T00:00:00.000+08:00|                           1440|                                   25.99|
|2017-11-07T00:00:00.000+08:00|                           1380|                                    26.0|
+-----------------------------+-------------------------------+----------------------------------------+
Total line number = 4
It costs 0.016s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br></div></div><p>值得注意的是，由于当前的FILL子句只能在某个时间点填充时间序列的缺失值，也就是说，FILL子句的执行结果恰好是一行，因此LIMIT和OFFSET不会是 与FILL子句结合使用，否则将提示错误。 例如，执行以下SQL语句：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select temperature from root.sgcc.wf03.wt01 where time = 2017-11-01T16:37:50.000 fill(float[previous, 1m]) limit 10
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>SQL语句将不会执行，并且相应的错误提示如下：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>Msg: 401: Error occured while parsing SQL to physical plan: line 1:101 mismatched input 'limit' expecting {&lt;EOF&gt;, SLIMIT, SOFFSET, GROUP, DISABLE, ALIGN}
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><ul><li>查询结果的列控制</li></ul> <p>通过使用SLIMIT和SOFFSET子句，用户可以与列相关的方式控制查询结果。 我们将通过以下示例演示如何使用SLIMIT和SOFFSET子句。</p> <ul><li>示例1：基本的SLIMIT子句</li></ul> <p>SQL语句是：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select * from root.ln.wf01.wt01 where time &gt; 2017-11-01T00:05:00.000 and time &lt; 2017-11-01T00:12:00.000 slimit 1
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>意思是：</p> <p>所选设备为ln组wf01工厂wt01设备； 所选时间序列是该设备下的第二列，即温度。 SQL语句要求在&quot;2017-11-01T00:05:00.000&quot;和&quot;2017-11-01T00:12:00.000&quot;的时间点之间选择温度传感器值。</p> <p>结果如下所示：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+-----------------------------+
|                         Time|root.ln.wf01.wt01.temperature|
+-----------------------------+-----------------------------+
|2017-11-01T00:06:00.000+08:00|                        20.71|
|2017-11-01T00:07:00.000+08:00|                        21.45|
|2017-11-01T00:08:00.000+08:00|                        22.58|
|2017-11-01T00:09:00.000+08:00|                        20.98|
|2017-11-01T00:10:00.000+08:00|                        25.52|
|2017-11-01T00:11:00.000+08:00|                        22.91|
+-----------------------------+-----------------------------+
Total line number = 6
It costs 0.000s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br></div></div><ul><li>示例2：带SOFFSET的SLIMIT子句</li></ul> <p>SQL语句是：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select * from root.ln.wf01.wt01 where time &gt; 2017-11-01T00:05:00.000 and time &lt; 2017-11-01T00:12:00.000 slimit 1 soffset 1
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>意思是：</p> <p>所选设备为ln组wf01工厂wt01设备； 所选时间序列是该设备下的第一列，即电源状态。 SQL语句要求在&quot; 2017-11-01T00:05:00.000&quot;和&quot;2017-11-01T00:12:00.000&quot;的时间点之间选择状态传感器值。</p> <p>结果如下所示：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+------------------------+
|                         Time|root.ln.wf01.wt01.status|
+-----------------------------+------------------------+
|2017-11-01T00:06:00.000+08:00|                   false|
|2017-11-01T00:07:00.000+08:00|                   false|
|2017-11-01T00:08:00.000+08:00|                   false|
|2017-11-01T00:09:00.000+08:00|                   false|
|2017-11-01T00:10:00.000+08:00|                    true|
|2017-11-01T00:11:00.000+08:00|                   false|
+-----------------------------+------------------------+
Total line number = 6
It costs 0.003s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br></div></div><ul><li>示例3：SLIMIT子句与GROUP BY子句结合</li></ul> <p>SQL语句是：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select max_value(*) from root.ln.wf01.wt01 group by ([2017-11-01T00:00:00, 2017-11-07T23:00:00),1d) slimit 1 soffset 1

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br></div></div><p>结果如下所示：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+-----------------------------------+
|                         Time|max_value(root.ln.wf01.wt01.status)|
+-----------------------------+-----------------------------------+
|2017-11-01T00:00:00.000+08:00|                               true|
|2017-11-02T00:00:00.000+08:00|                               true|
|2017-11-03T00:00:00.000+08:00|                               true|
|2017-11-04T00:00:00.000+08:00|                               true|
|2017-11-05T00:00:00.000+08:00|                               true|
|2017-11-06T00:00:00.000+08:00|                               true|
|2017-11-07T00:00:00.000+08:00|                               true|
+-----------------------------+-----------------------------------+
Total line number = 7
It costs 0.000s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br></div></div><ul><li>示例4：SLIMIT子句与FILL子句结合</li></ul> <p>SQL语句是：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select * from root.sgcc.wf03.wt01 where time = 2017-11-01T16:37:50.000 fill(float[previous, 1m]) slimit 1 soffset 1

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br></div></div><p>结果如下所示：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+--------------------------+
|                         Time|root.sgcc.wf03.wt01.status|
+-----------------------------+--------------------------+
|2017-11-01T16:35:00.000+08:00|                      true|
+-----------------------------+--------------------------+
Total line number = 1
It costs 0.007s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br></div></div><ul><li>控制查询结果的行和列</li></ul> <p>除了对查询结果进行行或列控制之外，IoTDB还允许用户控制查询结果的行和列。 这是同时包含LIMIT子句和SLIMIT子句的完整示例。</p> <p>SQL语句是：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select * from root.ln.wf01.wt01 limit 10 offset 100 slimit 2 soffset 0

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br></div></div><p>意思是：</p> <p>所选设备为ln组wf01工厂wt01设备； 所选时间序列是此设备下的第0列至第1列（第一列编号为第0列）。 SQL语句子句要求返回查询结果的第100至109行（第一行编号为0行）。</p> <p>结果如下所示：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+-----------------------------+------------------------+
|                         Time|root.ln.wf01.wt01.temperature|root.ln.wf01.wt01.status|
+-----------------------------+-----------------------------+------------------------+
|2017-11-01T01:40:00.000+08:00|                        21.19|                   false|
|2017-11-01T01:41:00.000+08:00|                        22.79|                   false|
|2017-11-01T01:42:00.000+08:00|                        22.98|                   false|
|2017-11-01T01:43:00.000+08:00|                        21.52|                   false|
|2017-11-01T01:44:00.000+08:00|                        23.45|                    true|
|2017-11-01T01:45:00.000+08:00|                        24.06|                    true|
|2017-11-01T01:46:00.000+08:00|                         22.6|                   false|
|2017-11-01T01:47:00.000+08:00|                        23.78|                    true|
|2017-11-01T01:48:00.000+08:00|                        24.72|                    true|
|2017-11-01T01:49:00.000+08:00|                        24.68|                    true|
+-----------------------------+-----------------------------+------------------------+
Total line number = 10
It costs 0.009s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br></div></div><h4 id="别名"><a href="#别名" class="header-anchor">#</a> 别名</h4> <p>由于 IoTDB 独特的数据模型，在每个传感器前都附带有设备等诸多额外信息。有时，我们只针对某个具体设备查询，而这些前缀信息频繁显示造成了冗余，影响了结果集的显示与分析。这时我们可以使用 IoTDB 提供的 AS 函数，将查询中出现的时间序列给定一个别名。</p> <p>例如：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select s1 as temperature, s2 as speed from root.ln.wf01.wt01;
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>则结果集将显示为：</p> <table><thead><tr><th>Time</th> <th>temperature</th> <th>speed</th></tr></thead> <tbody><tr><td>...</td> <td>...</td> <td>...</td></tr></tbody></table> <h4 id="内置函数"><a href="#内置函数" class="header-anchor">#</a> 内置函数</h4> <p>时间序列生成函数可接受若干原始时间序列作为输入，产生一列时间序列输出。与聚合函数不同的是，时间序列生成函数的结果集带有时间戳列。</p> <p>所有的时间序列生成函数都可以接受 * 作为输入，都可以与原始查询混合进行。</p> <ul><li>数学函数</li></ul> <p>目前IoTDB支持下列数学函数，这些数学函数的行为与这些函数在Java Math标准库中对应实现的行为一致。</p> <table><thead><tr><th>函数名</th> <th>输入序列类型</th> <th>输出序列类型</th> <th>Java标准库中的对应实现</th></tr></thead> <tbody><tr><td>SIN</td> <td>INT32 / INT64 / FLOAT / DOUBLE</td> <td>DOUBLE</td> <td>Math#sin(double)</td></tr> <tr><td>COS</td> <td>INT32 / INT64 / FLOAT / DOUBLE</td> <td>DOUBLE</td> <td>Math#cos(double)</td></tr> <tr><td>TAN</td> <td>INT32 / INT64 / FLOAT / DOUBLE</td> <td>DOUBLE</td> <td>Math#tan(double)</td></tr> <tr><td>ASIN</td> <td>INT32 / INT64 / FLOAT / DOUBLE</td> <td>DOUBLE</td> <td>Math#asin(double)</td></tr> <tr><td>ACOS</td> <td>INT32 / INT64 / FLOAT / DOUBLE</td> <td>DOUBLE</td> <td>Math#acos(double)</td></tr> <tr><td>ATAN</td> <td>INT32 / INT64 / FLOAT / DOUBLE</td> <td>DOUBLE</td> <td>Math#atan(double)</td></tr> <tr><td>DEGREES</td> <td>INT32 / INT64 / FLOAT / DOUBLE</td> <td>DOUBLE</td> <td>Math#toDegrees(double)</td></tr> <tr><td>RADIANS</td> <td>INT32 / INT64 / FLOAT / DOUBLE</td> <td>DOUBLE</td> <td>Math#toRadians(double)</td></tr> <tr><td>ABS</td> <td>INT32 / INT64 / FLOAT / DOUBLE</td> <td>与输入序列的实际类型一致</td> <td>Math#abs(int) / Math#abs(long) /Math#abs(float) /Math#abs(double)</td></tr> <tr><td>SIGN</td> <td>INT32 / INT64 / FLOAT / DOUBLE</td> <td>DOUBLE</td> <td>Math#signum(double)</td></tr> <tr><td>CEIL</td> <td>INT32 / INT64 / FLOAT / DOUBLE</td> <td>DOUBLE</td> <td>Math#ceil(double)</td></tr> <tr><td>FLOOR</td> <td>INT32 / INT64 / FLOAT / DOUBLE</td> <td>DOUBLE</td> <td>Math#floor(double)</td></tr> <tr><td>ROUND</td> <td>INT32 / INT64 / FLOAT / DOUBLE</td> <td>DOUBLE</td> <td>Math#rint(double)</td></tr> <tr><td>EXP</td> <td>INT32 / INT64 / FLOAT / DOUBLE</td> <td>DOUBLE</td> <td>Math#exp(double)</td></tr> <tr><td>LN</td> <td>INT32 / INT64 / FLOAT / DOUBLE</td> <td>DOUBLE</td> <td>Math#log(double)</td></tr> <tr><td>LOG10</td> <td>INT32 / INT64 / FLOAT / DOUBLE</td> <td>DOUBLE</td> <td>Math#log10(double)</td></tr> <tr><td>SQRT</td> <td>INT32 / INT64 / FLOAT / DOUBLE</td> <td>DOUBLE</td> <td>Math#sqrt(double)</td></tr></tbody></table> <p>例如：</p> <div class="language-sql line-numbers-mode"><pre class="language-sql"><code><span class="token keyword">select</span> s1<span class="token punctuation">,</span> sin<span class="token punctuation">(</span>s1<span class="token punctuation">)</span><span class="token punctuation">,</span> cos<span class="token punctuation">(</span>s1<span class="token punctuation">)</span><span class="token punctuation">,</span> tan<span class="token punctuation">(</span>s1<span class="token punctuation">)</span> <span class="token keyword">from</span> root<span class="token punctuation">.</span>sg1<span class="token punctuation">.</span>d1 <span class="token keyword">limit</span> <span class="token number">5</span> <span class="token keyword">offset</span> <span class="token number">1000</span><span class="token punctuation">;</span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>结果：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+-------------------+-------------------+--------------------+-------------------+
|                         Time|     root.sg1.d1.s1|sin(root.sg1.d1.s1)| cos(root.sg1.d1.s1)|tan(root.sg1.d1.s1)|
+-----------------------------+-------------------+-------------------+--------------------+-------------------+
|2020-12-10T17:11:49.037+08:00|7360723084922759782| 0.8133527237573284|  0.5817708713544664| 1.3980636773094157|
|2020-12-10T17:11:49.038+08:00|4377791063319964531|-0.8938962705202537|  0.4482738644511651| -1.994085181866842|
|2020-12-10T17:11:49.039+08:00|7972485567734642915| 0.9627757585308978|-0.27030138509681073|-3.5618602479083545|
|2020-12-10T17:11:49.040+08:00|2508858212791964081|-0.6073417341629443| -0.7944406950452296| 0.7644897069734913|
|2020-12-10T17:11:49.041+08:00|2817297431185141819|-0.8419358900502509| -0.5395775727782725| 1.5603611649667768|
+-----------------------------+-------------------+-------------------+--------------------+-------------------+
Total line number = 5
It costs 0.008s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><ul><li>字符串函数</li></ul> <p>目前IoTDB支持下列字符串处理函数：</p> <table><thead><tr><th>函数名</th> <th>输入序列类型</th> <th>必要的属性参数</th> <th>输出序列类型</th> <th>功能描述</th></tr></thead> <tbody><tr><td>STRING_CONTAINS</td> <td>TEXT</td> <td><code>s</code>: 待搜寻的字符串</td> <td>BOOLEAN</td> <td>判断字符串中是否存在<code>s</code></td></tr> <tr><td>STRING_MATCHES</td> <td>TEXT</td> <td><code>regex</code>: Java标准库风格的正则表达式</td> <td>BOOLEAN</td> <td>判断字符串是否能够被正则表达式<code>regex</code>匹配</td></tr></tbody></table> <p>例如：</p> <div class="language-sql line-numbers-mode"><pre class="language-sql"><code><span class="token keyword">select</span> s1<span class="token punctuation">,</span> string_contains<span class="token punctuation">(</span>s1<span class="token punctuation">,</span> <span class="token string">&quot;s&quot;</span><span class="token operator">=</span><span class="token string">&quot;warn&quot;</span><span class="token punctuation">)</span><span class="token punctuation">,</span> string_matches<span class="token punctuation">(</span>s1<span class="token punctuation">,</span> <span class="token string">&quot;regex&quot;</span><span class="token operator">=</span><span class="token string">&quot;[^\\s]+37229&quot;</span><span class="token punctuation">)</span> <span class="token keyword">from</span> root<span class="token punctuation">.</span>sg1<span class="token punctuation">.</span>d4<span class="token punctuation">;</span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>结果：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+--------------+-------------------------------------------+------------------------------------------------------+
|                         Time|root.sg1.d4.s1|string_contains(root.sg1.d4.s1, &quot;s&quot;=&quot;warn&quot;)|string_matches(root.sg1.d4.s1, &quot;regex&quot;=&quot;[^\\s]+37229&quot;)|
+-----------------------------+--------------+-------------------------------------------+------------------------------------------------------+
|1970-01-01T08:00:00.001+08:00|    warn:-8721|                                       true|                                                 false|
|1970-01-01T08:00:00.002+08:00|  error:-37229|                                      false|                                                  true|
|1970-01-01T08:00:00.003+08:00|     warn:1731|                                       true|                                                 false|
+-----------------------------+--------------+-------------------------------------------+------------------------------------------------------+
Total line number = 3
It costs 0.007s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br></div></div><ul><li>选择函数</li></ul> <p>目前IoTDB支持如下选择函数：</p> <table><thead><tr><th>函数名</th> <th>输入序列类型</th> <th>必要的属性参数</th> <th>输出序列类型</th> <th>功能描述</th></tr></thead> <tbody><tr><td>TOP_K</td> <td>INT32 / INT64 / FLOAT / DOUBLE / TEXT</td> <td><code>k</code>: 最多选择的数据点数，必须大于0小于等于1000</td> <td>与输入序列的实际类型一致</td> <td>返回某时间序列中值最大的<code>k</code>个数据点。若多于<code>k</code>个数据点的值并列最大，则返回时间戳最小的数据点。</td></tr> <tr><td>BOTTOM_K</td> <td>INT32 / INT64 / FLOAT / DOUBLE / TEXT</td> <td><code>k</code>: 最多选择的数据点数，必须大于0小于等于1000</td> <td>与输入序列的实际类型一致</td> <td>返回某时间序列中值最小的<code>k</code>个数据点。若多于<code>k</code>个数据点的值并列最小，则返回时间戳最小的数据点。</td></tr></tbody></table> <p>例如：</p> <div class="language-sql line-numbers-mode"><pre class="language-sql"><code><span class="token keyword">select</span> s1<span class="token punctuation">,</span> top_k<span class="token punctuation">(</span>s1<span class="token punctuation">,</span> <span class="token string">&quot;k&quot;</span><span class="token operator">=</span><span class="token string">&quot;2&quot;</span><span class="token punctuation">)</span><span class="token punctuation">,</span> bottom_k<span class="token punctuation">(</span>s1<span class="token punctuation">,</span> <span class="token string">&quot;k&quot;</span><span class="token operator">=</span><span class="token string">&quot;2&quot;</span><span class="token punctuation">)</span> <span class="token keyword">from</span> root<span class="token punctuation">.</span>sg1<span class="token punctuation">.</span>d2 <span class="token keyword">where</span> <span class="token keyword">time</span> <span class="token operator">&gt;</span> <span class="token number">2020</span><span class="token operator">-</span><span class="token number">12</span><span class="token operator">-</span><span class="token number">10</span>T20:<span class="token number">36</span>:<span class="token number">15.530</span><span class="token operator">+</span><span class="token number">08</span>:<span class="token number">00</span><span class="token punctuation">;</span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>结果：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+--------------------+------------------------------+---------------------------------+
|                         Time|      root.sg1.d2.s1|top_k(root.sg1.d2.s1, &quot;k&quot;=&quot;2&quot;)|bottom_k(root.sg1.d2.s1, &quot;k&quot;=&quot;2&quot;)|
+-----------------------------+--------------------+------------------------------+---------------------------------+
|2020-12-10T20:36:15.531+08:00| 1531604122307244742|           1531604122307244742|                             null|
|2020-12-10T20:36:15.532+08:00|-7426070874923281101|                          null|                             null|
|2020-12-10T20:36:15.533+08:00|-7162825364312197604|          -7162825364312197604|                             null|
|2020-12-10T20:36:15.534+08:00|-8581625725655917595|                          null|             -8581625725655917595|
|2020-12-10T20:36:15.535+08:00|-7667364751255535391|                          null|             -7667364751255535391|
+-----------------------------+--------------------+------------------------------+---------------------------------+
Total line number = 5
It costs 0.006s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><ul><li>趋势计算函数</li></ul> <p>目前IoTDB支持如下趋势计算函数：</p> <table><thead><tr><th>函数名</th> <th>输入序列类型</th> <th>输出序列类型</th> <th>功能描述</th></tr></thead> <tbody><tr><td>TIME_DIFFERENCE</td> <td>INT32 / INT64 / FLOAT / DOUBLE / BOOLEAN / TEXT</td> <td>INT64</td> <td>统计序列中某数据点的时间戳与前一数据点时间戳的差。范围内第一个数据点没有对应的结果输出。</td></tr> <tr><td>DIFFERENCE</td> <td>INT32 / INT64 / FLOAT / DOUBLE</td> <td>与输入序列的实际类型一致</td> <td>统计序列中某数据点的值与前一数据点的值的差。范围内第一个数据点没有对应的结果输出。</td></tr> <tr><td>NON_NEGATIVE_DIFFERENCE</td> <td>INT32 / INT64 / FLOAT / DOUBLE</td> <td>与输入序列的实际类型一致</td> <td>统计序列中某数据点的值与前一数据点的值的差的绝对值。范围内第一个数据点没有对应的结果输出。</td></tr> <tr><td>DERIVATIVE</td> <td>INT32 / INT64 / FLOAT / DOUBLE</td> <td>DOUBLE</td> <td>统计序列中某数据点相对于前一数据点的变化率，数量上等同于 DIFFERENCE /  TIME_DIFFERENCE。范围内第一个数据点没有对应的结果输出。</td></tr> <tr><td>NON_NEGATIVE_DERIVATIVE</td> <td>INT32 / INT64 / FLOAT / DOUBLE</td> <td>DOUBLE</td> <td>统计序列中某数据点相对于前一数据点的变化率的绝对值，数量上等同于 NON_NEGATIVE_DIFFERENCE /  TIME_DIFFERENCE。范围内第一个数据点没有对应的结果输出。</td></tr></tbody></table> <p>例如：</p> <div class="language-sql line-numbers-mode"><pre class="language-sql"><code><span class="token keyword">select</span> s1<span class="token punctuation">,</span> time_difference<span class="token punctuation">(</span>s1<span class="token punctuation">)</span><span class="token punctuation">,</span> difference<span class="token punctuation">(</span>s1<span class="token punctuation">)</span><span class="token punctuation">,</span> non_negative_difference<span class="token punctuation">(</span>s1<span class="token punctuation">)</span><span class="token punctuation">,</span> derivative<span class="token punctuation">(</span>s1<span class="token punctuation">)</span><span class="token punctuation">,</span> non_negative_derivative<span class="token punctuation">(</span>s1<span class="token punctuation">)</span> <span class="token keyword">from</span> root<span class="token punctuation">.</span>sg1<span class="token punctuation">.</span>d1 <span class="token keyword">limit</span> <span class="token number">5</span> <span class="token keyword">offset</span> <span class="token number">1000</span><span class="token punctuation">;</span> 
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>结果：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+-------------------+-------------------------------+--------------------------+---------------------------------------+--------------------------+---------------------------------------+
|                         Time|     root.sg1.d1.s1|time_difference(root.sg1.d1.s1)|difference(root.sg1.d1.s1)|non_negative_difference(root.sg1.d1.s1)|derivative(root.sg1.d1.s1)|non_negative_derivative(root.sg1.d1.s1)|
+-----------------------------+-------------------+-------------------------------+--------------------------+---------------------------------------+--------------------------+---------------------------------------+
|2020-12-10T17:11:49.037+08:00|7360723084922759782|                              1|      -8431715764844238876|                    8431715764844238876|    -8.4317157648442388E18|                  8.4317157648442388E18|
|2020-12-10T17:11:49.038+08:00|4377791063319964531|                              1|      -2982932021602795251|                    2982932021602795251|     -2.982932021602795E18|                   2.982932021602795E18|
|2020-12-10T17:11:49.039+08:00|7972485567734642915|                              1|       3594694504414678384|                    3594694504414678384|     3.5946945044146785E18|                  3.5946945044146785E18|
|2020-12-10T17:11:49.040+08:00|2508858212791964081|                              1|      -5463627354942678834|                    5463627354942678834|     -5.463627354942679E18|                   5.463627354942679E18|
|2020-12-10T17:11:49.041+08:00|2817297431185141819|                              1|        308439218393177738|                     308439218393177738|     3.0843921839317773E17|                  3.0843921839317773E17|
+-----------------------------+-------------------+-------------------------------+--------------------------+---------------------------------------+--------------------------+---------------------------------------+
Total line number = 5
It costs 0.014s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><ul><li>自定义序列生成函数</li></ul> <p>请参考 <a href="/zh/UserGuide/V0.12.x/UDF/UDF-User-Defined-Function.html">UDF (用户定义函数)</a>。</p> <h4 id="错误处理"><a href="#错误处理" class="header-anchor">#</a> 错误处理</h4> <p>当LIMIT / SLIMIT的参数N / SN超过结果集的大小时，IoTDB将按预期返回所有结果。 例如，原始SQL语句的查询结果由六行组成，我们通过LIMIT子句选择前100行：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select status,temperature from root.ln.wf01.wt01 where time &gt; 2017-11-01T00:05:00.000 and time &lt; 2017-11-01T00:12:00.000 limit 100

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br></div></div><p>结果如下所示：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+-----------------------------+------------------------+-----------------------------+
|                         Time|root.ln.wf01.wt01.status|root.ln.wf01.wt01.temperature|
+-----------------------------+------------------------+-----------------------------+
|2017-11-01T00:06:00.000+08:00|                   false|                        20.71|
|2017-11-01T00:07:00.000+08:00|                   false|                        21.45|
|2017-11-01T00:08:00.000+08:00|                   false|                        22.58|
|2017-11-01T00:09:00.000+08:00|                   false|                        20.98|
|2017-11-01T00:10:00.000+08:00|                    true|                        25.52|
|2017-11-01T00:11:00.000+08:00|                   false|                        22.91|
+-----------------------------+------------------------+-----------------------------+
Total line number = 6
It costs 0.005s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br></div></div><p>当LIMIT / SLIMIT子句的参数N / SN超过允许的最大值（N / SN的类型为int32）时，系统将提示错误。 例如，执行以下SQL语句：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select status,temperature from root.ln.wf01.wt01 where time &gt; 2017-11-01T00:05:00.000 and time &lt; 2017-11-01T00:12:00.000 limit 1234567890123456789

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br></div></div><p>SQL语句将不会执行，并且相应的错误提示如下：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>Msg: 303: check metadata error: Out of range. LIMIT &lt;N&gt;: N should be Int32.
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>当LIMIT / LIMIT子句的参数N / SN不是正整数时，系统将提示错误。 例如，执行以下SQL语句：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select status,temperature from root.ln.wf01.wt01 where time &gt; 2017-11-01T00:05:00.000 and time &lt; 2017-11-01T00:12:00.000 limit 13.1

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br></div></div><p>SQL语句将不会执行，并且相应的错误提示如下：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>Msg: 401: line 1:129 mismatched input '.' expecting {&lt;EOF&gt;, SLIMIT, OFFSET, SOFFSET, GROUP, DISABLE, ALIGN}
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>当LIMIT子句的参数OFFSET超过结果集的大小时，IoTDB将返回空结果集。 例如，执行以下SQL语句：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>select status,temperature from root.ln.wf01.wt01 where time &gt; 2017-11-01T00:05:00.000 and time &lt; 2017-11-01T00:12:00.000 limit 2 offset 6

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br></div></div><p>结果如下所示：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>+----+------------------------+-----------------------------+
|Time|root.ln.wf01.wt01.status|root.ln.wf01.wt01.temperature|
+----+------------------------+-----------------------------+
+----+------------------------+-----------------------------+
Empty set.
It costs 0.005s
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br></div></div><h3 id="数据删除"><a href="#数据删除" class="header-anchor">#</a> 数据删除</h3> <p>用户使用<a href="/zh/UserGuide/V0.12.x/Appendix/SQL-Reference.html">DELETE语句</a>可以删除指定的时间序列中符合时间删除条件的数据。在删除数据时，用户可以选择需要删除的一个或多个时间序列、时间序列的前缀、时间序列带*路径对某一个时间区间内的数据进行删除。</p> <p>在JAVA编程环境中，您可以使用JDBC API单条或批量执行DELETE语句。</p> <h4 id="单传感器时间序列值删除"><a href="#单传感器时间序列值删除" class="header-anchor">#</a> 单传感器时间序列值删除</h4> <p>以测控ln集团为例，存在这样的使用场景：</p> <p>wf02子站的wt02设备在2017-11-01 16:26:00之前的供电状态出现多段错误，且无法分析其正确数据，错误数据影响了与其他设备的关联分析。此时，需要将此时间段前的数据删除。进行此操作的SQL语句为：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>delete from root.ln.wf02.wt02.status where time&lt;=2017-11-01T16:26:00;
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>如果我们仅仅想要删除2017年内的在2017-11-01 16:26:00之前的数据，可以使用以下SQL:</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>delete from root.ln.wf02.wt02.status where time&gt;=2017-01-01T00:00:00 and time&lt;=2017-11-01T16:26:00;
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>IoTDB 支持删除一个时间序列任何一个时间范围内的所有时序点，用户可以使用以下SQL语句指定需要删除的时间范围：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>delete from root.ln.wf02.wt02.status where time &lt; 10
delete from root.ln.wf02.wt02.status where time &lt;= 10
delete from root.ln.wf02.wt02.status where time &lt; 20 and time &gt; 10
delete from root.ln.wf02.wt02.status where time &lt;= 20 and time &gt;= 10
delete from root.ln.wf02.wt02.status where time &gt; 20
delete from root.ln.wf02.wt02.status where time &gt;= 20
delete from root.ln.wf02.wt02.status where time = 20
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br></div></div><p>需要注意，当前的删除语句不支持where子句后的时间范围为多个由OR连接成的时间区间。如下删除语句将会解析出错：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>delete from root.ln.wf02.wt02.status where time &gt; 4 or time &lt; 0
Msg: 303: Check metadata error: For delete statement, where clause can only contain atomic
expressions like : time &gt; XXX, time &lt;= XXX, or two atomic expressions connected by 'AND'
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br></div></div><p>如果delete语句中未指定where子句，则会删除时间序列中的所有数据。</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>delete from root.ln.wf02.status
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><h4 id="多传感器时间序列值删除"><a href="#多传感器时间序列值删除" class="header-anchor">#</a> 多传感器时间序列值删除</h4> <p>当ln集团wf02子站的wt02设备在2017-11-01 16:26:00之前的供电状态和设备硬件版本都需要删除，此时可以使用含义更广的<a href="/zh/UserGuide/V0.12.x/Data-Concept/Data-Model-and-Terminology.html">前缀路径或带<code>*</code>路径</a>进行删除操作，进行此操作的SQL语句为：</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>delete from root.ln.wf02.wt02 where time &lt;= 2017-11-01T16:26:00;
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>或</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>delete from root.ln.wf02.wt02.* where time &lt;= 2017-11-01T16:26:00;
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>需要注意的是，当删除的路径不存在时，IoTDB会提示路径不存在，无法删除数据，如下所示。</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>IoTDB&gt; delete from root.ln.wf03.wt02.status where time &lt; now()
Msg: TimeSeries does not exist and its data cannot be deleted
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br></div></div><h4 id="删除时间分区-实验性功能"><a href="#删除时间分区-实验性功能" class="header-anchor">#</a> 删除时间分区 (实验性功能)</h4> <p>您可以通过如下语句来删除某一个存储组下的指定时间分区:</p> <div class="language- line-numbers-mode"><pre class="language-text"><code>DELETE PARTITION root.ln 0,1,2
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>上例中的0,1,2为待删除时间分区的id，您可以通过查看IoTDB的数据文件夹找到它，或者可以通过计算<code>timestamp / partitionInterval</code>(向下取整),
手动地将一个时间戳转换为对应的id，其中的<code>partitionInterval</code>可以在IoTDB的配置文件中找到（如果您使用的版本支持时间分区）。</p> <p>请注意该功能目前只是实验性的，如果您不是开发者，使用时请务必谨慎。</p></div> <div class="page-nav"><p class="inner"><span class="prev">
        ←
        <a href="/zh/UserGuide/V0.12.x/IoTDB-SQL-Language/DDL-Data-Definition-Language.html" class="prev">
          数据定义语言（DDL）
        </a></span> <span class="next"><a href="/zh/UserGuide/V0.12.x/IoTDB-SQL-Language/Maintenance-Command.html">
          运维命令
        </a>
        →
      </span></p></div> <p style="text-align: center;">Copyright © 2021 The Apache Software Foundation.<br>
     Apache and the Apache feather logo are trademarks of The Apache Software Foundation</p> <p style="text-align: center; margin-top: 10px; color: #444">
    Contact us: Join QQ Group 659990460 | Add friend <i>tietouqiao</i> and be invited to Wechat Group<br>
    see <a href="https://github.com/apache/iotdb/issues/1995">Join the community</a> for more</p></main></div><div class="global-ui"></div></div>
    <script src="/assets/js/app.13a2c569.js" defer></script><script src="/assets/js/3.7fccac46.js" defer></script><script src="/assets/js/552.2086fbe8.js" defer></script>
  </body>
</html>