| <!doctype html> |
| <html lang="en-US" data-theme="light"> |
| <head> |
| <meta charset="utf-8" /> |
| <meta name="viewport" content="width=device-width,initial-scale=1" /> |
| <meta name="generator" content="VuePress 2.0.0-rc.9" /> |
| <meta name="theme" content="VuePress Theme Hope 2.0.0-rc.34" /> |
| <style> |
| html { |
| background: var(--bg-color, #fff); |
| } |
| |
| html[data-theme="dark"] { |
| background: var(--bg-color, #1d1e1f); |
| } |
| |
| body { |
| background: var(--bg-color); |
| } |
| </style> |
| <script> |
| const userMode = localStorage.getItem("vuepress-theme-hope-scheme"); |
| const systemDarkMode = |
| window.matchMedia && |
| window.matchMedia("(prefers-color-scheme: dark)").matches; |
| |
| if (userMode === "dark" || (userMode !== "light" && systemDarkMode)) { |
| document.documentElement.setAttribute("data-theme", "dark"); |
| } |
| </script> |
| <link rel="alternate" hreflang="zh-cn" href="https://iotdb.apache.org/zh/UserGuide/V1.0.x/Query-Data/Group-By.html"><meta property="og:url" content="https://iotdb.apache.org/UserGuide/V1.0.x/Query-Data/Group-By.html"><meta property="og:site_name" content="IoTDB Website"><meta property="og:title" content="Group By Aggregate"><meta property="og:description" content="Group By Aggregate Aggregation By Level Aggregation by level statement is used to group the query result whose name is the same at the given level. Keyword LEVEL is used to spec..."><meta property="og:type" content="article"><meta property="og:locale" content="en-US"><meta property="og:locale:alternate" content="zh-CN"><meta property="og:updated_time" content="2023-07-10T03:11:17.000Z"><meta property="article:modified_time" content="2023-07-10T03:11:17.000Z"><script type="application/ld+json">{"@context":"https://schema.org","@type":"Article","headline":"Group By Aggregate","image":[""],"dateModified":"2023-07-10T03:11:17.000Z","author":[]}</script><link rel="icon" href="/favicon.ico"><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"><script type="text/javascript"> |
| var _paq = window._paq = window._paq || []; |
| /* tracker methods like "setCustomDimension" should be called before "trackPageView" */ |
| _paq.push(["setDoNotTrack", true]); |
| _paq.push(["disableCookies"]); |
| _paq.push(['trackPageView']); |
| _paq.push(['enableLinkTracking']); |
| (function() { |
| var u="https://analytics.apache.org/"; |
| _paq.push(['setTrackerUrl', u+'matomo.php']); |
| _paq.push(['setSiteId', '56']); |
| var d=document, g=d.createElement('script'), s=d.getElementsByTagName('script')[0]; |
| g.async=true; g.src=u+'matomo.js'; s.parentNode.insertBefore(g,s); |
| })(); |
| </script><title>Group By Aggregate | IoTDB Website</title><meta name="description" content="Group By Aggregate Aggregation By Level Aggregation by level statement is used to group the query result whose name is the same at the given level. Keyword LEVEL is used to spec..."> |
| <link rel="preload" href="/assets/style-DnEHAOmf.css" as="style"><link rel="stylesheet" href="/assets/style-DnEHAOmf.css"> |
| <link rel="modulepreload" href="/assets/app-DrPcRZG6.js"><link rel="modulepreload" href="/assets/Group-By.html-CMluBbXe.js"> |
| |
| </head> |
| <body> |
| <div id="app"><!--[--><!--[--><!--[--><span tabindex="-1"></span><a href="#main-content" class="vp-skip-link sr-only">Skip to main content</a><!--]--><!--[--><div class="theme-container has-toc"><!--[--><header id="navbar" class="vp-navbar hide-icon"><div class="vp-navbar-start"><button type="button" class="vp-toggle-sidebar-button" title="Toggle Sidebar"><span class="icon"></span></button><!--[--><!----><!--]--><!--[--><a class="route-link vp-brand" href="/"><img class="vp-nav-logo" src="/logo.png" alt><!----><span class="vp-site-name hide-in-pad">IoTDB Website</span></a><!--]--><!--[--><!----><!--]--></div><div class="vp-navbar-center"><!--[--><!----><!--]--><!--[--><!--]--><!--[--><!----><!--]--></div><div class="vp-navbar-end"><!--[--><!----><!--]--><!--[--><!--[--><div id="docsearch-container" style="display:none;"></div><div><button type="button" class="DocSearch DocSearch-Button" aria-label="Search"><span class="DocSearch-Button-Container"><svg width="20" height="20" class="DocSearch-Search-Icon" viewBox="0 0 20 20"><path d="M14.386 14.386l4.0877 4.0877-4.0877-4.0877c-2.9418 2.9419-7.7115 2.9419-10.6533 0-2.9419-2.9418-2.9419-7.7115 0-10.6533 2.9418-2.9419 7.7115-2.9419 10.6533 0 2.9419 2.9418 2.9419 7.7115 0 10.6533z" stroke="currentColor" fill="none" fill-rule="evenodd" stroke-linecap="round" stroke-linejoin="round"></path></svg><span class="DocSearch-Button-Placeholder">Search</span></span><span class="DocSearch-Button-Keys"><kbd class="DocSearch-Button-Key"><svg width="15" height="15" class="DocSearch-Control-Key-Icon"><path d="M4.505 4.496h2M5.505 5.496v5M8.216 4.496l.055 5.993M10 7.5c.333.333.5.667.5 1v2M12.326 4.5v5.996M8.384 4.496c1.674 0 2.116 0 2.116 1.5s-.442 1.5-2.116 1.5M3.205 9.303c-.09.448-.277 1.21-1.241 1.203C1 10.5.5 9.513.5 8V7c0-1.57.5-2.5 1.464-2.494.964.006 1.134.598 1.24 1.342M12.553 10.5h1.953" stroke-width="1.2" stroke="currentColor" fill="none" stroke-linecap="square"></path></svg></kbd><kbd class="DocSearch-Button-Key">K</kbd></span></button></div><!--]--><nav class="vp-nav-links"><div class="vp-nav-item hide-in-mobile"><div class="dropdown-wrapper"><button type="button" class="dropdown-title" aria-label="Documentation"><span class="title"><!---->Documentation</span><span class="arrow"></span><ul class="nav-dropdown"><li class="dropdown-item"><a class="route-link nav-link" href="/UserGuide/latest/QuickStart/QuickStart.html" aria-label="v1.3.x"><!---->v1.3.x<!----></a></li><li class="dropdown-item"><a class="route-link nav-link" href="/UserGuide/V1.2.x/QuickStart/QuickStart.html" aria-label="v1.2.x"><!---->v1.2.x<!----></a></li><li class="dropdown-item"><a class="route-link nav-link" href="/UserGuide/V1.1.x/QuickStart/QuickStart.html" aria-label="v1.1.x"><!---->v1.1.x<!----></a></li><li class="dropdown-item"><a class="route-link nav-link" href="/UserGuide/V1.0.x/QuickStart/QuickStart.html" aria-label="v1.0.x"><!---->v1.0.x<!----></a></li><li class="dropdown-item"><a class="route-link nav-link" href="/UserGuide/V0.13.x/QuickStart/QuickStart.html" aria-label="v0.13.x"><!---->v0.13.x<!----></a></li></ul></button></div></div><div class="vp-nav-item hide-in-mobile"><a href="https://cwiki.apache.org/confluence/display/IOTDB/System+Design" rel="noopener noreferrer" target="_blank" aria-label="Design" class="nav-link"><!---->Design<span><svg class="external-link-icon" 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"><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="external-link-icon-sr-only">open in new window</span></span><!----></a></div><div class="vp-nav-item hide-in-mobile"><a class="route-link nav-link" href="/Download/" aria-label="Download"><!---->Download<!----></a></div><div class="vp-nav-item hide-in-mobile"><div class="dropdown-wrapper"><button type="button" class="dropdown-title" aria-label="Community"><span class="title"><!---->Community</span><span class="arrow"></span><ul class="nav-dropdown"><li class="dropdown-item"><a class="route-link nav-link" href="/Community/About.html" aria-label="About"><!---->About<!----></a></li><li class="dropdown-item"><a href="https://cwiki.apache.org/confluence/display/iotdb" rel="noopener noreferrer" target="_blank" aria-label="Wiki" class="nav-link"><!---->Wiki<span><svg class="external-link-icon" 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"><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="external-link-icon-sr-only">open in new window</span></span><!----></a></li><li class="dropdown-item"><a class="route-link nav-link" href="/Community/Community-Project-Committers.html" aria-label="People"><!---->People<!----></a></li><li class="dropdown-item"><a class="route-link nav-link" href="/Community/Community-Powered-By.html" aria-label="Powered By"><!---->Powered By<!----></a></li><li class="dropdown-item"><a class="route-link nav-link" href="/Community/Materials.html" aria-label="Resources"><!---->Resources<!----></a></li><li class="dropdown-item"><a class="route-link nav-link" href="/Community/Feedback.html" aria-label="Feedback"><!---->Feedback<!----></a></li></ul></button></div></div><div class="vp-nav-item hide-in-mobile"><div class="dropdown-wrapper"><button type="button" class="dropdown-title" aria-label="Development"><span class="title"><!---->Development</span><span class="arrow"></span><ul class="nav-dropdown"><li class="dropdown-item"><a class="route-link nav-link" href="/Development/VoteRelease.html" aria-label="How to vote"><!---->How to vote<!----></a></li><li class="dropdown-item"><a class="route-link nav-link" href="/Development/HowToCommit.html" aria-label="How to Commit"><!---->How to Commit<!----></a></li><li class="dropdown-item"><a class="route-link nav-link" href="/Development/HowToJoin.html" aria-label="Become a Contributor"><!---->Become a Contributor<!----></a></li><li class="dropdown-item"><a class="route-link nav-link" href="/Development/Committer.html" aria-label="Become a Committer"><!---->Become a Committer<!----></a></li><li class="dropdown-item"><a class="route-link nav-link" href="/Development/ContributeGuide.html" aria-label="ContributeGuide"><!---->ContributeGuide<!----></a></li><li class="dropdown-item"><a class="route-link nav-link" href="/Development/HowtoContributeCode.html" aria-label="How to Contribute Code"><!---->How to Contribute Code<!----></a></li><li class="dropdown-item"><a class="route-link nav-link" href="/Development/format-changelist.html" aria-label="Changelist of TsFile"><!---->Changelist of TsFile<!----></a></li><li class="dropdown-item"><a class="route-link nav-link" href="/Development/rpc-changelist.html" aria-label="Changelist of RPC"><!---->Changelist of RPC<!----></a></li></ul></button></div></div><div class="vp-nav-item hide-in-mobile"><div class="dropdown-wrapper"><button type="button" class="dropdown-title" aria-label="ASF"><span class="title"><!---->ASF</span><span class="arrow"></span><ul class="nav-dropdown"><li class="dropdown-item"><a href="https://www.apache.org/" rel="noopener noreferrer" target="_blank" aria-label="Foundation" class="nav-link"><!---->Foundation<span><svg class="external-link-icon" 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"><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="external-link-icon-sr-only">open in new window</span></span><!----></a></li><li class="dropdown-item"><a href="https://www.apache.org/licenses/" rel="noopener noreferrer" target="_blank" aria-label="License" class="nav-link"><!---->License<span><svg class="external-link-icon" 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"><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="external-link-icon-sr-only">open in new window</span></span><!----></a></li><li class="dropdown-item"><a href="https://www.apache.org/security/" rel="noopener noreferrer" target="_blank" aria-label="Security" class="nav-link"><!---->Security<span><svg class="external-link-icon" 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"><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="external-link-icon-sr-only">open in new window</span></span><!----></a></li><li class="dropdown-item"><a href="https://www.apache.org/foundation/sponsorship.html" rel="noopener noreferrer" target="_blank" aria-label="Sponsorship" class="nav-link"><!---->Sponsorship<span><svg class="external-link-icon" 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"><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="external-link-icon-sr-only">open in new window</span></span><!----></a></li><li class="dropdown-item"><a href="https://www.apache.org/foundation/thanks.html" rel="noopener noreferrer" target="_blank" aria-label="Thanks" class="nav-link"><!---->Thanks<span><svg class="external-link-icon" 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"><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="external-link-icon-sr-only">open in new window</span></span><!----></a></li><li class="dropdown-item"><a href="https://www.apache.org/events/current-event" rel="noopener noreferrer" target="_blank" aria-label="Current Events" class="nav-link"><!---->Current Events<span><svg class="external-link-icon" 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"><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="external-link-icon-sr-only">open in new window</span></span><!----></a></li><li class="dropdown-item"><a href="https://privacy.apache.org/policies/privacy-policy-public.html" rel="noopener noreferrer" target="_blank" aria-label="Privacy" class="nav-link"><!---->Privacy<span><svg class="external-link-icon" 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"><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="external-link-icon-sr-only">open in new window</span></span><!----></a></li></ul></button></div></div></nav><div class="vp-nav-item"><div class="dropdown-wrapper"><button type="button" class="dropdown-title" aria-label="Select language"><!--[--><svg xmlns="http://www.w3.org/2000/svg" class="icon i18n-icon" viewBox="0 0 1024 1024" fill="currentColor" aria-label="i18n icon" style="width:1rem;height:1rem;vertical-align:middle;"><path d="M379.392 460.8 494.08 575.488l-42.496 102.4L307.2 532.48 138.24 701.44l-71.68-72.704L234.496 460.8l-45.056-45.056c-27.136-27.136-51.2-66.56-66.56-108.544h112.64c7.68 14.336 16.896 27.136 26.112 35.84l45.568 46.08 45.056-45.056C382.976 312.32 409.6 247.808 409.6 204.8H0V102.4h256V0h102.4v102.4h256v102.4H512c0 70.144-37.888 161.28-87.04 210.944L378.88 460.8zM576 870.4 512 1024H409.6l256-614.4H768l256 614.4H921.6l-64-153.6H576zM618.496 768h196.608L716.8 532.48 618.496 768z"></path></svg><!--]--><span class="arrow"></span><ul class="nav-dropdown"><li class="dropdown-item"><a class="route-link nav-link active" href="/UserGuide/V1.0.x/Query-Data/Group-By.html" aria-label="English"><!---->English<!----></a></li><li class="dropdown-item"><a class="route-link nav-link" href="/zh/UserGuide/V1.0.x/Query-Data/Group-By.html" aria-label="简体中文"><!---->简体中文<!----></a></li></ul></button></div></div><div class="vp-nav-item hide-in-mobile"><button type="button" id="appearance-switch"><svg xmlns="http://www.w3.org/2000/svg" class="icon auto-icon" viewBox="0 0 1024 1024" fill="currentColor" aria-label="auto icon" style="display:none;"><path d="M512 992C246.92 992 32 777.08 32 512S246.92 32 512 32s480 214.92 480 480-214.92 480-480 480zm0-840c-198.78 0-360 161.22-360 360 0 198.84 161.22 360 360 360s360-161.16 360-360c0-198.78-161.22-360-360-360zm0 660V212c165.72 0 300 134.34 300 300 0 165.72-134.28 300-300 300z"></path></svg><svg xmlns="http://www.w3.org/2000/svg" class="icon dark-icon" viewBox="0 0 1024 1024" fill="currentColor" aria-label="dark icon" style="display:none;"><path d="M524.8 938.667h-4.267a439.893 439.893 0 0 1-313.173-134.4 446.293 446.293 0 0 1-11.093-597.334A432.213 432.213 0 0 1 366.933 90.027a42.667 42.667 0 0 1 45.227 9.386 42.667 42.667 0 0 1 10.24 42.667 358.4 358.4 0 0 0 82.773 375.893 361.387 361.387 0 0 0 376.747 82.774 42.667 42.667 0 0 1 54.187 55.04 433.493 433.493 0 0 1-99.84 154.88 438.613 438.613 0 0 1-311.467 128z"></path></svg><svg xmlns="http://www.w3.org/2000/svg" class="icon light-icon" viewBox="0 0 1024 1024" fill="currentColor" aria-label="light icon" style="display:block;"><path d="M952 552h-80a40 40 0 0 1 0-80h80a40 40 0 0 1 0 80zM801.88 280.08a41 41 0 0 1-57.96-57.96l57.96-58a41.04 41.04 0 0 1 58 58l-58 57.96zM512 752a240 240 0 1 1 0-480 240 240 0 0 1 0 480zm0-560a40 40 0 0 1-40-40V72a40 40 0 0 1 80 0v80a40 40 0 0 1-40 40zm-289.88 88.08-58-57.96a41.04 41.04 0 0 1 58-58l57.96 58a41 41 0 0 1-57.96 57.96zM192 512a40 40 0 0 1-40 40H72a40 40 0 0 1 0-80h80a40 40 0 0 1 40 40zm30.12 231.92a41 41 0 0 1 57.96 57.96l-57.96 58a41.04 41.04 0 0 1-58-58l58-57.96zM512 832a40 40 0 0 1 40 40v80a40 40 0 0 1-80 0v-80a40 40 0 0 1 40-40zm289.88-88.08 58 57.96a41.04 41.04 0 0 1-58 58l-57.96-58a41 41 0 0 1 57.96-57.96z"></path></svg></button></div><div class="vp-nav-item vp-action"><a class="vp-action-link" href="https://github.com/apache/iotdb" target="_blank" rel="noopener noreferrer" aria-label="GitHub"><svg xmlns="http://www.w3.org/2000/svg" class="icon github-icon" viewBox="0 0 1024 1024" fill="currentColor" aria-label="github icon" style="width:1.25rem;height:1.25rem;vertical-align:middle;"><path d="M511.957 21.333C241.024 21.333 21.333 240.981 21.333 512c0 216.832 140.544 400.725 335.574 465.664 24.49 4.395 32.256-10.07 32.256-23.083 0-11.69.256-44.245 0-85.205-136.448 29.61-164.736-64.64-164.736-64.64-22.315-56.704-54.4-71.765-54.4-71.765-44.587-30.464 3.285-29.824 3.285-29.824 49.195 3.413 75.179 50.517 75.179 50.517 43.776 75.008 114.816 53.333 142.762 40.79 4.523-31.66 17.152-53.377 31.19-65.537-108.971-12.458-223.488-54.485-223.488-242.602 0-53.547 19.114-97.323 50.517-131.67-5.035-12.33-21.93-62.293 4.779-129.834 0 0 41.258-13.184 134.912 50.346a469.803 469.803 0 0 1 122.88-16.554c41.642.213 83.626 5.632 122.88 16.554 93.653-63.488 134.784-50.346 134.784-50.346 26.752 67.541 9.898 117.504 4.864 129.834 31.402 34.347 50.474 78.123 50.474 131.67 0 188.586-114.73 230.016-224.042 242.09 17.578 15.232 33.578 44.672 33.578 90.454v135.85c0 13.142 7.936 27.606 32.854 22.87C862.25 912.597 1002.667 728.747 1002.667 512c0-271.019-219.648-490.667-490.71-490.667z"></path></svg></a></div><!--]--><!--[--><!----><!--]--><button type="button" class="vp-toggle-navbar-button" aria-label="Toggle Navbar" aria-expanded="false" aria-controls="nav-screen"><span><span class="vp-top"></span><span class="vp-middle"></span><span class="vp-bottom"></span></span></button></div></header><!----><!--]--><!----><div class="toggle-sidebar-wrapper"><span class="arrow start"></span></div><aside id="sidebar" class="vp-sidebar"><!--[--><!----><!--]--><ul class="vp-sidebar-links"><li><section class="vp-sidebar-group"><p class="vp-sidebar-header"><!----><span class="vp-sidebar-title">IoTDB User Guide (V1.0.x)</span><!----></p><ul class="vp-sidebar-links"></ul></section></li><li><section class="vp-sidebar-group"><button class="vp-sidebar-header clickable" type="button"><!----><span class="vp-sidebar-title">About IoTDB</span><span class="vp-arrow end"></span></button><!----></section></li><li><section class="vp-sidebar-group"><button class="vp-sidebar-header clickable" type="button"><!----><span class="vp-sidebar-title">Quick Start</span><span class="vp-arrow end"></span></button><!----></section></li><li><section class="vp-sidebar-group"><button class="vp-sidebar-header clickable" type="button"><!----><span class="vp-sidebar-title">Data Concept</span><span class="vp-arrow end"></span></button><!----></section></li><li><section class="vp-sidebar-group"><button class="vp-sidebar-header clickable" type="button"><!----><span class="vp-sidebar-title">Syntax Conventions</span><span class="vp-arrow end"></span></button><!----></section></li><li><section class="vp-sidebar-group"><button class="vp-sidebar-header clickable" type="button"><!----><span class="vp-sidebar-title">API</span><span class="vp-arrow end"></span></button><!----></section></li><li><section class="vp-sidebar-group"><button class="vp-sidebar-header clickable" type="button"><!----><span class="vp-sidebar-title">Operate Metadata</span><span class="vp-arrow end"></span></button><!----></section></li><li><section class="vp-sidebar-group"><button class="vp-sidebar-header clickable" type="button"><!----><span class="vp-sidebar-title">Write Data (Update Data)</span><span class="vp-arrow end"></span></button><!----></section></li><li><section class="vp-sidebar-group"><button class="vp-sidebar-header clickable" type="button"><!----><span class="vp-sidebar-title">Delete Data</span><span class="vp-arrow end"></span></button><!----></section></li><li><section class="vp-sidebar-group"><button class="vp-sidebar-header clickable active" type="button"><!----><span class="vp-sidebar-title">Query Data</span><span class="vp-arrow down"></span></button><ul class="vp-sidebar-links"><li><a class="route-link nav-link vp-sidebar-link vp-sidebar-page" href="/UserGuide/V1.0.x/Query-Data/Overview.html" aria-label="Overview"><!---->Overview<!----></a></li><li><a class="route-link nav-link vp-sidebar-link vp-sidebar-page" href="/UserGuide/V1.0.x/Query-Data/Select-Expression.html" aria-label="Select Expression"><!---->Select Expression<!----></a></li><li><a class="route-link nav-link vp-sidebar-link vp-sidebar-page" href="/UserGuide/V1.0.x/Query-Data/Last-Query.html" aria-label="Last Query"><!---->Last Query<!----></a></li><li><a class="route-link nav-link vp-sidebar-link vp-sidebar-page" href="/UserGuide/V1.0.x/Query-Data/Align-By.html" aria-label="Query Alignment Mode"><!---->Query Alignment Mode<!----></a></li><li><a class="route-link nav-link vp-sidebar-link vp-sidebar-page" href="/UserGuide/V1.0.x/Query-Data/Where-Condition.html" aria-label="Where Condition"><!---->Where Condition<!----></a></li><li><a class="route-link nav-link active vp-sidebar-link vp-sidebar-page active" href="/UserGuide/V1.0.x/Query-Data/Group-By.html" aria-label="Group By"><!---->Group By<!----></a></li><li><a class="route-link nav-link vp-sidebar-link vp-sidebar-page" href="/UserGuide/V1.0.x/Query-Data/Having-Condition.html" aria-label="Having Condition"><!---->Having Condition<!----></a></li><li><a class="route-link nav-link vp-sidebar-link vp-sidebar-page" href="/UserGuide/V1.0.x/Query-Data/Fill.html" aria-label="Fill Null Value"><!---->Fill Null Value<!----></a></li><li><a class="route-link nav-link vp-sidebar-link vp-sidebar-page" href="/UserGuide/V1.0.x/Query-Data/Pagination.html" aria-label="Pagination"><!---->Pagination<!----></a></li><li><a class="route-link nav-link vp-sidebar-link vp-sidebar-page" href="/UserGuide/V1.0.x/Query-Data/Select-Into.html" aria-label="Select Into"><!---->Select Into<!----></a></li><li><a class="route-link nav-link vp-sidebar-link vp-sidebar-page" href="/UserGuide/V1.0.x/Query-Data/Continuous-Query.html" aria-label="Continuous Query"><!---->Continuous Query<!----></a></li></ul></section></li><li><section class="vp-sidebar-group"><button class="vp-sidebar-header clickable" type="button"><!----><span class="vp-sidebar-title">Operators and Functions</span><span class="vp-arrow end"></span></button><!----></section></li><li><section class="vp-sidebar-group"><button class="vp-sidebar-header clickable" type="button"><!----><span class="vp-sidebar-title">Trigger</span><span class="vp-arrow end"></span></button><!----></section></li><li><section class="vp-sidebar-group"><button class="vp-sidebar-header clickable" type="button"><!----><span class="vp-sidebar-title">Monitor and Alert</span><span class="vp-arrow end"></span></button><!----></section></li><li><section class="vp-sidebar-group"><button class="vp-sidebar-header clickable" type="button"><!----><span class="vp-sidebar-title">Administration Management</span><span class="vp-arrow end"></span></button><!----></section></li><li><section class="vp-sidebar-group"><button class="vp-sidebar-header clickable" type="button"><!----><span class="vp-sidebar-title">Maintenance Tools</span><span class="vp-arrow end"></span></button><!----></section></li><li><section class="vp-sidebar-group"><button class="vp-sidebar-header clickable" type="button"><!----><span class="vp-sidebar-title">Collaboration of Edge and Cloud</span><span class="vp-arrow end"></span></button><!----></section></li><li><section class="vp-sidebar-group"><button class="vp-sidebar-header clickable" type="button"><!----><span class="vp-sidebar-title">Ecosystem Integration</span><span class="vp-arrow end"></span></button><!----></section></li><li><section class="vp-sidebar-group"><button class="vp-sidebar-header clickable" type="button"><!----><span class="vp-sidebar-title">Cluster</span><span class="vp-arrow end"></span></button><!----></section></li><li><section class="vp-sidebar-group"><button class="vp-sidebar-header clickable" type="button"><!----><span class="vp-sidebar-title">FAQ</span><span class="vp-arrow end"></span></button><!----></section></li><li><section class="vp-sidebar-group"><button class="vp-sidebar-header clickable" type="button"><!----><span class="vp-sidebar-title">Reference</span><span class="vp-arrow end"></span></button><!----></section></li></ul><!--[--><!----><!--]--></aside><!--[--><main id="main-content" class="vp-page"><!--[--><!--[--><!----><!--]--><!----><nav class="vp-breadcrumb disable"></nav><div class="vp-page-title"><h1><!---->Group By Aggregate</h1><div class="page-info"><!----><!----><span class="page-date-info" aria-label="Writing Date"><svg xmlns="http://www.w3.org/2000/svg" class="icon calendar-icon" viewBox="0 0 1024 1024" fill="currentColor" aria-label="calendar icon"><path d="M716.4 110.137c0-18.753-14.72-33.473-33.472-33.473-18.753 0-33.473 14.72-33.473 33.473v33.473h66.993v-33.473zm-334.87 0c0-18.753-14.72-33.473-33.473-33.473s-33.52 14.72-33.52 33.473v33.473h66.993v-33.473zm468.81 33.52H716.4v100.465c0 18.753-14.72 33.473-33.472 33.473a33.145 33.145 0 01-33.473-33.473V143.657H381.53v100.465c0 18.753-14.72 33.473-33.473 33.473a33.145 33.145 0 01-33.473-33.473V143.657H180.6A134.314 134.314 0 0046.66 277.595v535.756A134.314 134.314 0 00180.6 947.289h669.74a134.36 134.36 0 00133.94-133.938V277.595a134.314 134.314 0 00-133.94-133.938zm33.473 267.877H147.126a33.145 33.145 0 01-33.473-33.473c0-18.752 14.72-33.473 33.473-33.473h736.687c18.752 0 33.472 14.72 33.472 33.473a33.145 33.145 0 01-33.472 33.473z"></path></svg><span><!----></span><meta property="datePublished" content="2023-07-10T03:11:17.000Z"></span><span class="page-pageview-info" aria-label="Page views"><svg xmlns="http://www.w3.org/2000/svg" class="icon eye-icon" viewBox="0 0 1024 1024" fill="currentColor" aria-label="eye icon"><path d="M992 512.096c0-5.76-.992-10.592-1.28-11.136-.192-2.88-1.152-8.064-2.08-10.816-.256-.672-.544-1.376-.832-2.08-.48-1.568-1.024-3.104-1.6-4.32C897.664 290.112 707.104 160 512 160c-195.072 0-385.632 130.016-473.76 322.592-1.056 2.112-1.792 4.096-2.272 5.856a55.512 55.512 0 00-.64 1.6c-1.76 5.088-1.792 8.64-1.632 7.744-.832 3.744-1.568 11.168-1.568 11.168-.224 2.272-.224 4.032.032 6.304 0 0 .736 6.464 1.088 7.808.128 1.824.576 4.512 1.12 6.976h-.032c.448 2.08 1.12 4.096 1.984 6.08.48 1.536.992 2.976 1.472 4.032C126.432 733.856 316.992 864 512 864c195.136 0 385.696-130.048 473.216-321.696 1.376-2.496 2.24-4.832 2.848-6.912.256-.608.48-1.184.672-1.728 1.536-4.48 1.856-8.32 1.728-8.32l-.032.032c.608-3.104 1.568-7.744 1.568-13.28zM512 672c-88.224 0-160-71.776-160-160s71.776-160 160-160 160 71.776 160 160-71.776 160-160 160z"></path></svg><span id="ArtalkPV" class="vp-pageview waline-pageview-count" data-path="/UserGuide/V1.0.x/Query-Data/Group-By.html" data-page-key="/UserGuide/V1.0.x/Query-Data/Group-By.html">...</span></span><span class="page-reading-time-info" aria-label="Reading Time"><svg xmlns="http://www.w3.org/2000/svg" class="icon timer-icon" viewBox="0 0 1024 1024" fill="currentColor" aria-label="timer icon"><path d="M799.387 122.15c4.402-2.978 7.38-7.897 7.38-13.463v-1.165c0-8.933-7.38-16.312-16.312-16.312H256.33c-8.933 0-16.311 7.38-16.311 16.312v1.165c0 5.825 2.977 10.874 7.637 13.592 4.143 194.44 97.22 354.963 220.201 392.763-122.204 37.542-214.893 196.511-220.2 389.397-4.661 5.049-7.638 11.651-7.638 19.03v5.825h566.49v-5.825c0-7.379-2.849-13.981-7.509-18.9-5.049-193.016-97.867-351.985-220.2-389.527 123.24-37.67 216.446-198.453 220.588-392.892zM531.16 450.445v352.632c117.674 1.553 211.787 40.778 211.787 88.676H304.097c0-48.286 95.149-87.382 213.728-88.676V450.445c-93.077-3.107-167.901-81.297-167.901-177.093 0-8.803 6.99-15.793 15.793-15.793 8.803 0 15.794 6.99 15.794 15.793 0 80.261 63.69 145.635 142.01 145.635s142.011-65.374 142.011-145.635c0-8.803 6.99-15.793 15.794-15.793s15.793 6.99 15.793 15.793c0 95.019-73.789 172.82-165.96 177.093z"></path></svg><span>About 14 min</span><meta property="timeRequired" content="PT14M"></span><!----><!----></div><hr></div><div class="vp-toc-placeholder"><aside id="toc"><!--[--><!----><!--]--><div class="vp-toc-header">On This Page<button type="button" class="print-button" title="Print"><svg xmlns="http://www.w3.org/2000/svg" class="icon print-icon" viewBox="0 0 1024 1024" fill="currentColor" aria-label="print icon"><path d="M819.2 364.8h-44.8V128c0-17.067-14.933-32-32-32H281.6c-17.067 0-32 14.933-32 32v236.8h-44.8C145.067 364.8 96 413.867 96 473.6v192c0 59.733 49.067 108.8 108.8 108.8h44.8V896c0 17.067 14.933 32 32 32h460.8c17.067 0 32-14.933 32-32V774.4h44.8c59.733 0 108.8-49.067 108.8-108.8v-192c0-59.733-49.067-108.8-108.8-108.8zM313.6 160h396.8v204.8H313.6V160zm396.8 704H313.6V620.8h396.8V864zM864 665.6c0 25.6-19.2 44.8-44.8 44.8h-44.8V588.8c0-17.067-14.933-32-32-32H281.6c-17.067 0-32 14.933-32 32v121.6h-44.8c-25.6 0-44.8-19.2-44.8-44.8v-192c0-25.6 19.2-44.8 44.8-44.8h614.4c25.6 0 44.8 19.2 44.8 44.8v192z"></path></svg></button><div class="arrow end"></div></div><div class="vp-toc-wrapper"><ul class="vp-toc-list"><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level2" href="#aggregation-by-level">Aggregation By Level</a></li><!----><!--]--><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level2" href="#downsampling-aggregate-query">Downsampling Aggregate Query</a></li><li><ul class="vp-toc-list"><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level3" href="#downsampling-aggregate-query-without-specifying-the-sliding-step-length">Downsampling Aggregate Query without Specifying the Sliding Step Length</a></li><!----><!--]--><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level3" href="#downsampling-aggregate-query-specifying-the-sliding-step-length">Downsampling Aggregate Query Specifying the Sliding Step Length</a></li><!----><!--]--><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level3" href="#downsampling-aggregate-query-by-natural-month">Downsampling Aggregate Query by Natural Month</a></li><!----><!--]--><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level3" href="#left-open-and-right-close-range">Left Open And Right Close Range</a></li><!----><!--]--></ul></li><!--]--><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level2" href="#downsampling-aggregate-query-with-level-clause">Downsampling Aggregate Query with Level Clause</a></li><!----><!--]--><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level2" href="#aggregation-by-tags">Aggregation By Tags</a></li><li><ul class="vp-toc-list"><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level3" href="#aggregation-query-by-one-single-tag">Aggregation query by one single tag</a></li><!----><!--]--><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level3" href="#aggregation-query-by-multiple-tags">Aggregation query by multiple tags</a></li><!----><!--]--><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level3" href="#downsampling-aggregation-by-tags-based-on-time-window">Downsampling Aggregation by tags based on Time Window</a></li><!----><!--]--><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level3" href="#limitation-of-aggregation-by-tags">Limitation of Aggregation by Tags</a></li><!----><!--]--></ul></li><!--]--></ul><div class="vp-toc-marker" style="top:-1.7rem;"></div></div><!--[--><!----><!--]--></aside></div><!--[--><!----><!--]--><div class="theme-hope-content"><h1 id="group-by-aggregate" tabindex="-1"><a class="header-anchor" href="#group-by-aggregate"><span>Group By Aggregate</span></a></h1><h2 id="aggregation-by-level" tabindex="-1"><a class="header-anchor" href="#aggregation-by-level"><span>Aggregation By Level</span></a></h2><p>Aggregation by level statement is used to group the query result whose name is the same at the given level.</p><ul><li>Keyword <code>LEVEL</code> is used to specify the level that need to be grouped. By convention, <code>level=0</code> represents <em>root</em> level.</li><li>All aggregation functions are supported. When using five aggregations: sum, avg, min_value, max_value and extreme, please make sure all the aggregated series have exactly the same data type. Otherwise, it will generate a syntax error.</li></ul><p><strong>Example 1:</strong> there are multiple series named <code>status</code> under different databases， like "root.ln.wf01.wt01.status", "root.ln.wf02.wt02.status", and "root.sgcc.wf03.wt01.status". If you need to count the number of data points of the <code>status</code> sequence under different databases, use the following query:</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">select</span> <span class="token function">count</span><span class="token punctuation">(</span><span class="token keyword">status</span><span class="token punctuation">)</span> <span class="token keyword">from</span> root<span class="token punctuation">.</span><span class="token operator">*</span><span class="token operator">*</span> <span class="token keyword">group</span> <span class="token keyword">by</span> <span class="token keyword">level</span> <span class="token operator">=</span> <span class="token number">1</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>Result：</p><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><pre class="language-text"><code>+-------------------------+---------------------------+ |
| |count(root.ln.*.*.status)|count(root.sgcc.*.*.status)| |
| +-------------------------+---------------------------+ |
| | 20160| 10080| |
| +-------------------------+---------------------------+ |
| Total line number = 1 |
| It costs 0.003s |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p><strong>Example 2:</strong> If you need to count the number of data points under different devices, you can specify level = 3,</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">select</span> <span class="token function">count</span><span class="token punctuation">(</span><span class="token keyword">status</span><span class="token punctuation">)</span> <span class="token keyword">from</span> root<span class="token punctuation">.</span><span class="token operator">*</span><span class="token operator">*</span> <span class="token keyword">group</span> <span class="token keyword">by</span> <span class="token keyword">level</span> <span class="token operator">=</span> <span class="token number">3</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>Result：</p><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><pre class="language-text"><code>+---------------------------+---------------------------+ |
| |count(root.*.*.wt01.status)|count(root.*.*.wt02.status)| |
| +---------------------------+---------------------------+ |
| | 20160| 10080| |
| +---------------------------+---------------------------+ |
| Total line number = 1 |
| It costs 0.003s |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p><strong>Example 3:</strong> Attention，the devices named <code>wt01</code> under databases <code>ln</code> and <code>sgcc</code> are grouped together, since they are regarded as devices with the same name. If you need to further count the number of data points in different devices under different databases, you can use the following query:</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">select</span> <span class="token function">count</span><span class="token punctuation">(</span><span class="token keyword">status</span><span class="token punctuation">)</span> <span class="token keyword">from</span> root<span class="token punctuation">.</span><span class="token operator">*</span><span class="token operator">*</span> <span class="token keyword">group</span> <span class="token keyword">by</span> <span class="token keyword">level</span> <span class="token operator">=</span> <span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">3</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>Result：</p><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><pre class="language-text"><code>+----------------------------+----------------------------+------------------------------+ |
| |count(root.ln.*.wt01.status)|count(root.ln.*.wt02.status)|count(root.sgcc.*.wt01.status)| |
| +----------------------------+----------------------------+------------------------------+ |
| | 10080| 10080| 10080| |
| +----------------------------+----------------------------+------------------------------+ |
| Total line number = 1 |
| It costs 0.003s |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p><strong>Example 4:</strong> Assuming that you want to query the maximum value of temperature sensor under all time series, you can use the following query statement:</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">select</span> max_value<span class="token punctuation">(</span>temperature<span class="token punctuation">)</span> <span class="token keyword">from</span> root<span class="token punctuation">.</span><span class="token operator">*</span><span class="token operator">*</span> <span class="token keyword">group</span> <span class="token keyword">by</span> <span class="token keyword">level</span> <span class="token operator">=</span> <span class="token number">0</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>Result：</p><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><pre class="language-text"><code>+---------------------------------+ |
| |max_value(root.*.*.*.temperature)| |
| +---------------------------------+ |
| | 26.0| |
| +---------------------------------+ |
| Total line number = 1 |
| It costs 0.013s |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p><strong>Example 5:</strong> The above queries are for a certain sensor. In particular, <strong>if you want to query the total data points owned by all sensors at a certain level</strong>, you need to explicitly specify <code>*</code> is selected.</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">select</span> <span class="token function">count</span><span class="token punctuation">(</span><span class="token operator">*</span><span class="token punctuation">)</span> <span class="token keyword">from</span> root<span class="token punctuation">.</span>ln<span class="token punctuation">.</span><span class="token operator">*</span><span class="token operator">*</span> <span class="token keyword">group</span> <span class="token keyword">by</span> <span class="token keyword">level</span> <span class="token operator">=</span> <span class="token number">2</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>Result：</p><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><pre class="language-text"><code>+----------------------+----------------------+ |
| |count(root.*.wf01.*.*)|count(root.*.wf02.*.*)| |
| +----------------------+----------------------+ |
| | 20160| 20160| |
| +----------------------+----------------------+ |
| Total line number = 1 |
| It costs 0.013s |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h2 id="downsampling-aggregate-query" tabindex="-1"><a class="header-anchor" href="#downsampling-aggregate-query"><span>Downsampling Aggregate Query</span></a></h2><p>Segmentation aggregation is a typical query method for time series data. Data is collected at high frequency and needs to be aggregated and calculated at certain time intervals. For example, to calculate the daily average temperature, the sequence of temperature needs to be segmented by day, and then calculated. average value.</p><p>Downsampling query refers to a query method that uses a lower frequency than the time frequency of data collection, and is a special case of segmented aggregation. For example, the frequency of data collection is one second. If you want to display the data in one minute, you need to use downsampling query.</p><p>This section mainly introduces the related examples of downsampling aggregation query, using the <code>GROUP BY</code> clause. IoTDB supports partitioning result sets according to time interval and customized sliding step. And by default results are sorted by time in ascending order.</p><p>The GROUP BY statement provides users with three types of specified parameters:</p><ul><li>Parameter 1: The display window on the time axis</li><li>Parameter 2: Time interval for dividing the time axis(should be positive)</li><li>Parameter 3: Time sliding step (optional and defaults to equal the time interval if not set)</li></ul><p>The actual meanings of the three types of parameters are shown in Figure below.<br> Among them, the parameter 3 is optional.</p><center><img style="width:100%;max-width:800px;max-height:600px;margin-left:auto;margin-right:auto;display:block;" src="https://alioss.timecho.com/docs/img/github/69109512-f808bc80-0ab2-11ea-9e4d-b2b2f58fb474.png"></center><p>There are three typical examples of frequency reduction aggregation:</p><h3 id="downsampling-aggregate-query-without-specifying-the-sliding-step-length" tabindex="-1"><a class="header-anchor" href="#downsampling-aggregate-query-without-specifying-the-sliding-step-length"><span>Downsampling Aggregate Query without Specifying the Sliding Step Length</span></a></h3><p>The SQL statement is:</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">select</span> <span class="token function">count</span><span class="token punctuation">(</span><span class="token keyword">status</span><span class="token punctuation">)</span><span class="token punctuation">,</span> max_value<span class="token punctuation">(</span>temperature<span class="token punctuation">)</span> <span class="token keyword">from</span> root<span class="token punctuation">.</span>ln<span class="token punctuation">.</span>wf01<span class="token punctuation">.</span>wt01 <span class="token keyword">group</span> <span class="token keyword">by</span> <span class="token punctuation">(</span><span class="token punctuation">[</span><span class="token number">2017</span><span class="token operator">-</span><span class="token number">11</span><span class="token operator">-</span><span class="token number">01</span>T00:<span class="token number">00</span>:<span class="token number">00</span><span class="token punctuation">,</span> <span class="token number">2017</span><span class="token operator">-</span><span class="token number">11</span><span class="token operator">-</span><span class="token number">07</span>T23:<span class="token number">00</span>:<span class="token number">00</span><span class="token punctuation">)</span><span class="token punctuation">,</span><span class="token number">1</span>d<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>which means:</p><p>Since the sliding step length is not specified, the GROUP BY statement by default set the sliding step the same as the time interval which is <code>1d</code>.</p><p>The fist parameter of the GROUP BY statement above is the display window parameter, which determines the final display range is [2017-11-01T00:00:00, 2017-11-07T23:00:00).</p><p>The second parameter of the GROUP BY statement above is the time interval for dividing the time axis. Taking this parameter (1d) as time interval and startTime of the display window as the dividing origin, the time axis is divided into several continuous intervals, which are [0,1d), [1d, 2d), [2d, 3d), etc.</p><p>Then the system will use the time and value filtering condition in the WHERE clause and the first parameter of the GROUP BY statement as the data filtering condition to obtain the data satisfying the filtering condition (which in this case is the data in the range of [2017-11-01T00:00:00, 2017-11-07 T23:00:00]), and map these data to the previously segmented time axis (in this case there are mapped data in every 1-day period from 2017-11-01T00:00:00 to 2017-11-07T23:00:00:00).</p><p>Since there is data for each time period in the result range to be displayed, the execution result of the SQL statement is shown below:</p><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><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" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h3 id="downsampling-aggregate-query-specifying-the-sliding-step-length" tabindex="-1"><a class="header-anchor" href="#downsampling-aggregate-query-specifying-the-sliding-step-length"><span>Downsampling Aggregate Query Specifying the Sliding Step Length</span></a></h3><p>The SQL statement is:</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">select</span> <span class="token function">count</span><span class="token punctuation">(</span><span class="token keyword">status</span><span class="token punctuation">)</span><span class="token punctuation">,</span> max_value<span class="token punctuation">(</span>temperature<span class="token punctuation">)</span> <span class="token keyword">from</span> root<span class="token punctuation">.</span>ln<span class="token punctuation">.</span>wf01<span class="token punctuation">.</span>wt01 <span class="token keyword">group</span> <span class="token keyword">by</span> <span class="token punctuation">(</span><span class="token punctuation">[</span><span class="token number">2017</span><span class="token operator">-</span><span class="token number">11</span><span class="token operator">-</span><span class="token number">01</span> <span class="token number">00</span>:<span class="token number">00</span>:<span class="token number">00</span><span class="token punctuation">,</span> <span class="token number">2017</span><span class="token operator">-</span><span class="token number">11</span><span class="token operator">-</span><span class="token number">07</span> <span class="token number">23</span>:<span class="token number">00</span>:<span class="token number">00</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token number">3</span>h<span class="token punctuation">,</span> <span class="token number">1</span>d<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>which means:</p><p>Since the user specifies the sliding step parameter as 1d, the GROUP BY statement will move the time interval <code>1 day</code> long instead of <code>3 hours</code> as default.</p><p>That means we want to fetch all the data of 00:00:00 to 02:59:59 every day from 2017-11-01 to 2017-11-07.</p><p>The first parameter of the GROUP BY statement above is the display window parameter, which determines the final display range is [2017-11-01T00:00:00, 2017-11-07T23:00:00).</p><p>The second parameter of the GROUP BY statement above is the time interval for dividing the time axis. Taking this parameter (3h) as time interval and the startTime of the display window as the dividing origin, the time axis is divided into several continuous intervals, which are [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), etc.</p><p>The third parameter of the GROUP BY statement above is the sliding step for each time interval moving.</p><p>Then the system will use the time and value filtering condition in the WHERE clause and the first parameter of the GROUP BY statement as the data filtering condition to obtain the data satisfying the filtering condition (which in this case is the data in the range of [2017-11-01T00:00:00, 2017-11-07T23:00:00]), and map these data to the previously segmented time axis (in this case there are mapped data in every 3-hour period for each day from 2017-11-01T00:00:00 to 2017-11-07T23:00:00:00).</p><p>Since there is data for each time period in the result range to be displayed, the execution result of the SQL statement is shown below:</p><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><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" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>The sliding step can be smaller than the interval, in which case there is overlapping time between the aggregation windows (similar to a sliding window).</p><p>The SQL statement is:</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">select</span> <span class="token function">count</span><span class="token punctuation">(</span><span class="token keyword">status</span><span class="token punctuation">)</span><span class="token punctuation">,</span> max_value<span class="token punctuation">(</span>temperature<span class="token punctuation">)</span> <span class="token keyword">from</span> root<span class="token punctuation">.</span>ln<span class="token punctuation">.</span>wf01<span class="token punctuation">.</span>wt01 <span class="token keyword">group</span> <span class="token keyword">by</span> <span class="token punctuation">(</span><span class="token punctuation">[</span><span class="token number">2017</span><span class="token operator">-</span><span class="token number">11</span><span class="token operator">-</span><span class="token number">01</span> <span class="token number">00</span>:<span class="token number">00</span>:<span class="token number">00</span><span class="token punctuation">,</span> <span class="token number">2017</span><span class="token operator">-</span><span class="token number">11</span><span class="token operator">-</span><span class="token number">01</span> <span class="token number">10</span>:<span class="token number">00</span>:<span class="token number">00</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token number">4</span>h<span class="token punctuation">,</span> <span class="token number">2</span>h<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>The execution result of the SQL statement is shown below:</p><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><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| |
| |2017-11-01T02:00:00.000+08:00| 180| 25.98| |
| |2017-11-01T04:00:00.000+08:00| 180| 25.96| |
| |2017-11-01T06:00:00.000+08:00| 180| 25.96| |
| |2017-11-01T08:00:00.000+08:00| 180| 26.0| |
| +-----------------------------+-------------------------------+----------------------------------------+ |
| Total line number = 5 |
| It costs 0.006s |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h3 id="downsampling-aggregate-query-by-natural-month" tabindex="-1"><a class="header-anchor" href="#downsampling-aggregate-query-by-natural-month"><span>Downsampling Aggregate Query by Natural Month</span></a></h3><p>The SQL statement is:</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">select</span> <span class="token function">count</span><span class="token punctuation">(</span><span class="token keyword">status</span><span class="token punctuation">)</span> <span class="token keyword">from</span> root<span class="token punctuation">.</span>ln<span class="token punctuation">.</span>wf01<span class="token punctuation">.</span>wt01 <span class="token keyword">group</span> <span class="token keyword">by</span><span class="token punctuation">(</span><span class="token punctuation">[</span><span class="token number">2017</span><span class="token operator">-</span><span class="token number">11</span><span class="token operator">-</span><span class="token number">01</span>T00:<span class="token number">00</span>:<span class="token number">00</span><span class="token punctuation">,</span> <span class="token number">2019</span><span class="token operator">-</span><span class="token number">11</span><span class="token operator">-</span><span class="token number">07</span>T23:<span class="token number">00</span>:<span class="token number">00</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token number">1</span>mo<span class="token punctuation">,</span> <span class="token number">2</span>mo<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>which means:</p><p>Since the user specifies the sliding step parameter as <code>2mo</code>, the GROUP BY statement will move the time interval <code>2 months</code> long instead of <code>1 month</code> as default.</p><p>The first parameter of the GROUP BY statement above is the display window parameter, which determines the final display range is [2017-11-01T00:00:00, 2019-11-07T23:00:00).</p><p>The start time is 2017-11-01T00:00:00. The sliding step will increment monthly based on the start date, and the 1st day of the month will be used as the time interval's start time.</p><p>The second parameter of the GROUP BY statement above is the time interval for dividing the time axis. Taking this parameter (1mo) as time interval and the startTime of the display window as the dividing origin, the time axis is divided into several continuous intervals, which are [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)), etc.</p><p>The third parameter of the GROUP BY statement above is the sliding step for each time interval moving.</p><p>Then the system will use the time and value filtering condition in the WHERE clause and the first parameter of the GROUP BY statement as the data filtering condition to obtain the data satisfying the filtering condition (which in this case is the data in the range of (2017-11-01T00:00:00, 2019-11-07T23:00:00], and map these data to the previously segmented time axis (in this case there are mapped data of the first month in every two month period from 2017-11-01T00:00:00 to 2019-11-07T23:00:00).</p><p>The SQL execution result is:</p><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><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" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>The SQL statement is:</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">select</span> <span class="token function">count</span><span class="token punctuation">(</span><span class="token keyword">status</span><span class="token punctuation">)</span> <span class="token keyword">from</span> root<span class="token punctuation">.</span>ln<span class="token punctuation">.</span>wf01<span class="token punctuation">.</span>wt01 <span class="token keyword">group</span> <span class="token keyword">by</span><span class="token punctuation">(</span><span class="token punctuation">[</span><span class="token number">2017</span><span class="token operator">-</span><span class="token number">10</span><span class="token operator">-</span><span class="token number">31</span>T00:<span class="token number">00</span>:<span class="token number">00</span><span class="token punctuation">,</span> <span class="token number">2019</span><span class="token operator">-</span><span class="token number">11</span><span class="token operator">-</span><span class="token number">07</span>T23:<span class="token number">00</span>:<span class="token number">00</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token number">1</span>mo<span class="token punctuation">,</span> <span class="token number">2</span>mo<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>which means:</p><p>Since the user specifies the sliding step parameter as <code>2mo</code>, the GROUP BY statement will move the time interval <code>2 months</code> long instead of <code>1 month</code> as default.</p><p>The first parameter of the GROUP BY statement above is the display window parameter, which determines the final display range is [2017-10-31T00:00:00, 2019-11-07T23:00:00).</p><p>Different from the previous example, the start time is set to 2017-10-31T00:00:00. The sliding step will increment monthly based on the start date, and the 31st day of the month meaning the last day of the month will be used as the time interval's start time. If the start time is set to the 30th date, the sliding step will use the 30th or the last day of the month.</p><p>The start time is 2017-10-31T00:00:00. The sliding step will increment monthly based on the start time, and the 1st day of the month will be used as the time interval's start time.</p><p>The second parameter of the GROUP BY statement above is the time interval for dividing the time axis. Taking this parameter (1mo) as time interval and the startTime of the display window as the dividing origin, the time axis is divided into several continuous intervals, which are [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), etc.</p><p>The third parameter of the GROUP BY statement above is the sliding step for each time interval moving.</p><p>Then the system will use the time and value filtering condition in the WHERE clause and the first parameter of the GROUP BY statement as the data filtering condition to obtain the data satisfying the filtering condition (which in this case is the data in the range of [2017-10-31T00:00:00, 2019-11-07T23:00:00) and map these data to the previously segmented time axis (in this case there are mapped data of the first month in every two month period from 2017-10-31T00:00:00 to 2019-11-07T23:00:00).</p><p>The SQL execution result is:</p><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><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" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h3 id="left-open-and-right-close-range" tabindex="-1"><a class="header-anchor" href="#left-open-and-right-close-range"><span>Left Open And Right Close Range</span></a></h3><p>The SQL statement is:</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">select</span> <span class="token function">count</span><span class="token punctuation">(</span><span class="token keyword">status</span><span class="token punctuation">)</span> <span class="token keyword">from</span> root<span class="token punctuation">.</span>ln<span class="token punctuation">.</span>wf01<span class="token punctuation">.</span>wt01 <span class="token keyword">group</span> <span class="token keyword">by</span> <span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token number">2017</span><span class="token operator">-</span><span class="token number">11</span><span class="token operator">-</span><span class="token number">01</span>T00:<span class="token number">00</span>:<span class="token number">00</span><span class="token punctuation">,</span> <span class="token number">2017</span><span class="token operator">-</span><span class="token number">11</span><span class="token operator">-</span><span class="token number">07</span>T23:<span class="token number">00</span>:<span class="token number">00</span><span class="token punctuation">]</span><span class="token punctuation">,</span><span class="token number">1</span>d<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>In this sql, the time interval is left open and right close, so we won't include the value of timestamp 2017-11-01T00:00:00 and instead we will include the value of timestamp 2017-11-07T23:00:00.</p><p>We will get the result like following:</p><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><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" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h2 id="downsampling-aggregate-query-with-level-clause" tabindex="-1"><a class="header-anchor" href="#downsampling-aggregate-query-with-level-clause"><span>Downsampling Aggregate Query with Level Clause</span></a></h2><p>Level could be defined to show count the number of points of each node at the given level in current Metadata Tree.</p><p>This could be used to query the number of points under each device.</p><p>The SQL statement is:</p><p>Get downsampling aggregate query by level.</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">select</span> <span class="token function">count</span><span class="token punctuation">(</span><span class="token keyword">status</span><span class="token punctuation">)</span> <span class="token keyword">from</span> root<span class="token punctuation">.</span>ln<span class="token punctuation">.</span>wf01<span class="token punctuation">.</span>wt01 <span class="token keyword">group</span> <span class="token keyword">by</span> <span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token number">2017</span><span class="token operator">-</span><span class="token number">11</span><span class="token operator">-</span><span class="token number">01</span>T00:<span class="token number">00</span>:<span class="token number">00</span><span class="token punctuation">,</span> <span class="token number">2017</span><span class="token operator">-</span><span class="token number">11</span><span class="token operator">-</span><span class="token number">07</span>T23:<span class="token number">00</span>:<span class="token number">00</span><span class="token punctuation">]</span><span class="token punctuation">,</span><span class="token number">1</span>d<span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token keyword">level</span><span class="token operator">=</span><span class="token number">1</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>Result:</p><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><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" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>Downsampling aggregate query with sliding step and by level.</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">select</span> <span class="token function">count</span><span class="token punctuation">(</span><span class="token keyword">status</span><span class="token punctuation">)</span> <span class="token keyword">from</span> root<span class="token punctuation">.</span>ln<span class="token punctuation">.</span>wf01<span class="token punctuation">.</span>wt01 <span class="token keyword">group</span> <span class="token keyword">by</span> <span class="token punctuation">(</span><span class="token punctuation">[</span><span class="token number">2017</span><span class="token operator">-</span><span class="token number">11</span><span class="token operator">-</span><span class="token number">01</span> <span class="token number">00</span>:<span class="token number">00</span>:<span class="token number">00</span><span class="token punctuation">,</span> <span class="token number">2017</span><span class="token operator">-</span><span class="token number">11</span><span class="token operator">-</span><span class="token number">07</span> <span class="token number">23</span>:<span class="token number">00</span>:<span class="token number">00</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token number">3</span>h<span class="token punctuation">,</span> <span class="token number">1</span>d<span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token keyword">level</span><span class="token operator">=</span><span class="token number">1</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>Result:</p><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><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" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h2 id="aggregation-by-tags" tabindex="-1"><a class="header-anchor" href="#aggregation-by-tags"><span>Aggregation By Tags</span></a></h2><p>IotDB allows you to do aggregation query with the tags defined in timeseries through <code>GROUP BY TAGS</code> clause as well.</p><p>Firstly, we can put these example data into IoTDB, which will be used in the following feature introduction.</p><p>These are the temperature data of the workshops, which belongs to the factory <code>factory1</code> and locates in different cities. The time range is <code>[1000, 10000)</code>.</p><p>The device node of the timeseries path is the ID of the device. The information of city and workshop are modelled in the tags <code>city</code> and <code>workshop</code>.<br> The devices <code>d1</code> and <code>d2</code> belong to the workshop <code>d1</code> in <code>Beijing</code>.<br><code>d3</code> and <code>d4</code> belong to the workshop <code>w2</code> in <code>Beijing</code>.<br><code>d5</code> and <code>d6</code> belong to the workshop <code>w1</code> in <code>Shanghai</code>.<br><code>d7</code> belongs to the workshop <code>w2</code> in <code>Shanghai</code>.<br><code>d8</code> and <code>d9</code> are under maintenance, and don't belong to any workshops, so they have no tags.</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">CREATE</span> <span class="token keyword">DATABASE</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">;</span> |
| <span class="token keyword">create</span> timeseries root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d1<span class="token punctuation">.</span>temperature <span class="token keyword">with</span> datatype<span class="token operator">=</span><span class="token keyword">FLOAT</span> tags<span class="token punctuation">(</span>city<span class="token operator">=</span>Beijing<span class="token punctuation">,</span> workshop<span class="token operator">=</span>w1<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">create</span> timeseries root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d2<span class="token punctuation">.</span>temperature <span class="token keyword">with</span> datatype<span class="token operator">=</span><span class="token keyword">FLOAT</span> tags<span class="token punctuation">(</span>city<span class="token operator">=</span>Beijing<span class="token punctuation">,</span> workshop<span class="token operator">=</span>w1<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">create</span> timeseries root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d3<span class="token punctuation">.</span>temperature <span class="token keyword">with</span> datatype<span class="token operator">=</span><span class="token keyword">FLOAT</span> tags<span class="token punctuation">(</span>city<span class="token operator">=</span>Beijing<span class="token punctuation">,</span> workshop<span class="token operator">=</span>w2<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">create</span> timeseries root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d4<span class="token punctuation">.</span>temperature <span class="token keyword">with</span> datatype<span class="token operator">=</span><span class="token keyword">FLOAT</span> tags<span class="token punctuation">(</span>city<span class="token operator">=</span>Beijing<span class="token punctuation">,</span> workshop<span class="token operator">=</span>w2<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">create</span> timeseries root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d5<span class="token punctuation">.</span>temperature <span class="token keyword">with</span> datatype<span class="token operator">=</span><span class="token keyword">FLOAT</span> tags<span class="token punctuation">(</span>city<span class="token operator">=</span>Shanghai<span class="token punctuation">,</span> workshop<span class="token operator">=</span>w1<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">create</span> timeseries root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d6<span class="token punctuation">.</span>temperature <span class="token keyword">with</span> datatype<span class="token operator">=</span><span class="token keyword">FLOAT</span> tags<span class="token punctuation">(</span>city<span class="token operator">=</span>Shanghai<span class="token punctuation">,</span> workshop<span class="token operator">=</span>w1<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">create</span> timeseries root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d7<span class="token punctuation">.</span>temperature <span class="token keyword">with</span> datatype<span class="token operator">=</span><span class="token keyword">FLOAT</span> tags<span class="token punctuation">(</span>city<span class="token operator">=</span>Shanghai<span class="token punctuation">,</span> workshop<span class="token operator">=</span>w2<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">create</span> timeseries root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d8<span class="token punctuation">.</span>temperature <span class="token keyword">with</span> datatype<span class="token operator">=</span><span class="token keyword">FLOAT</span><span class="token punctuation">;</span> |
| <span class="token keyword">create</span> timeseries root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d9<span class="token punctuation">.</span>temperature <span class="token keyword">with</span> datatype<span class="token operator">=</span><span class="token keyword">FLOAT</span><span class="token punctuation">;</span> |
| |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d1<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">1000</span><span class="token punctuation">,</span> <span class="token number">104.0</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d1<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">3000</span><span class="token punctuation">,</span> <span class="token number">104.2</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d1<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">5000</span><span class="token punctuation">,</span> <span class="token number">103.3</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d1<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">7000</span><span class="token punctuation">,</span> <span class="token number">104.1</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d2<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">1000</span><span class="token punctuation">,</span> <span class="token number">104.4</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d2<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">3000</span><span class="token punctuation">,</span> <span class="token number">103.7</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d2<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">5000</span><span class="token punctuation">,</span> <span class="token number">103.3</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d2<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">7000</span><span class="token punctuation">,</span> <span class="token number">102.9</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d3<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">1000</span><span class="token punctuation">,</span> <span class="token number">103.9</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d3<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">3000</span><span class="token punctuation">,</span> <span class="token number">103.8</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d3<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">5000</span><span class="token punctuation">,</span> <span class="token number">102.7</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d3<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">7000</span><span class="token punctuation">,</span> <span class="token number">106.9</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d4<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">1000</span><span class="token punctuation">,</span> <span class="token number">103.9</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d4<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">5000</span><span class="token punctuation">,</span> <span class="token number">102.7</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d4<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">7000</span><span class="token punctuation">,</span> <span class="token number">106.9</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d5<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">1000</span><span class="token punctuation">,</span> <span class="token number">112.9</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d5<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">7000</span><span class="token punctuation">,</span> <span class="token number">113.0</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d6<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">1000</span><span class="token punctuation">,</span> <span class="token number">113.9</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d6<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">3000</span><span class="token punctuation">,</span> <span class="token number">113.3</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d6<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">5000</span><span class="token punctuation">,</span> <span class="token number">112.7</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d6<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">7000</span><span class="token punctuation">,</span> <span class="token number">112.3</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d7<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">1000</span><span class="token punctuation">,</span> <span class="token number">101.2</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d7<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">3000</span><span class="token punctuation">,</span> <span class="token number">99.3</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d7<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">5000</span><span class="token punctuation">,</span> <span class="token number">100.1</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d7<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">7000</span><span class="token punctuation">,</span> <span class="token number">99.8</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d8<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">1000</span><span class="token punctuation">,</span> <span class="token number">50.0</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d8<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">3000</span><span class="token punctuation">,</span> <span class="token number">52.1</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d8<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">5000</span><span class="token punctuation">,</span> <span class="token number">50.1</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d8<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">7000</span><span class="token punctuation">,</span> <span class="token number">50.5</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d9<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">1000</span><span class="token punctuation">,</span> <span class="token number">50.3</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">insert</span> <span class="token keyword">into</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span>d9<span class="token punctuation">(</span><span class="token keyword">time</span><span class="token punctuation">,</span> temperature<span class="token punctuation">)</span> <span class="token keyword">values</span><span class="token punctuation">(</span><span class="token number">3000</span><span class="token punctuation">,</span> <span class="token number">52.1</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h3 id="aggregation-query-by-one-single-tag" tabindex="-1"><a class="header-anchor" href="#aggregation-query-by-one-single-tag"><span>Aggregation query by one single tag</span></a></h3><p>If the user wants to know the average temperature of each workshop, he can query like this</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">SELECT</span> <span class="token function">AVG</span><span class="token punctuation">(</span>temperature<span class="token punctuation">)</span> <span class="token keyword">FROM</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span><span class="token operator">*</span><span class="token operator">*</span> <span class="token keyword">GROUP</span> <span class="token keyword">BY</span> TAGS<span class="token punctuation">(</span>city<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>The query will calculate the average of the temperatures of those timeseries which have the same tag value of the key <code>city</code>.<br> The results are</p><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><pre class="language-text"><code>+--------+------------------+ |
| | city| avg(temperature)| |
| +--------+------------------+ |
| | Beijing|104.04666697184244| |
| |Shanghai|107.85000076293946| |
| | NULL| 50.84999910990397| |
| +--------+------------------+ |
| Total line number = 3 |
| It costs 0.231s |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>From the results we can see that the differences between aggregation by tags query and aggregation by time or level query are:</p><ol><li>Aggregation query by tags will no longer remove wildcard to raw timeseries, but do the aggregation through the data of multiple timeseries, which have the same tag value.</li><li>Except for the aggregate result column, the result set contains the key-value column of the grouped tag. The column name is the tag key, and the values in the column are tag values which present in the searched timeseries.<br> If some searched timeseries doesn't have the grouped tag, a <code>NULL</code> value in the key-value column of the grouped tag will be presented, which means the aggregation of all the timeseries lacking the tagged key.</li></ol><h3 id="aggregation-query-by-multiple-tags" tabindex="-1"><a class="header-anchor" href="#aggregation-query-by-multiple-tags"><span>Aggregation query by multiple tags</span></a></h3><p>Except for the aggregation query by one single tag, aggregation query by multiple tags in a particular order is allowed as well.</p><p>For example, a user wants to know the average temperature of the devices in each workshop.<br> As the workshop names may be same in different city, it's not correct to aggregated by the tag <code>workshop</code> directly.<br> So the aggregation by the tag <code>city</code> should be done first, and then by the tag <code>workshop</code>.</p><p>SQL</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">SELECT</span> <span class="token function">avg</span><span class="token punctuation">(</span>temperature<span class="token punctuation">)</span> <span class="token keyword">FROM</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span><span class="token operator">*</span><span class="token operator">*</span> <span class="token keyword">GROUP</span> <span class="token keyword">BY</span> TAGS<span class="token punctuation">(</span>city<span class="token punctuation">,</span> workshop<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>The results</p><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><pre class="language-text"><code>+--------+--------+------------------+ |
| | city|workshop| avg(temperature)| |
| +--------+--------+------------------+ |
| | NULL| NULL| 50.84999910990397| |
| |Shanghai| w1|113.01666768391927| |
| | Beijing| w2| 104.4000004359654| |
| |Shanghai| w2|100.10000038146973| |
| | Beijing| w1|103.73750019073486| |
| +--------+--------+------------------+ |
| Total line number = 5 |
| It costs 0.027s |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>We can see that in a multiple tags aggregation query, the result set will output the key-value columns of all the grouped tag keys, which have the same order with the one in <code>GROUP BY TAGS</code>.</p><h3 id="downsampling-aggregation-by-tags-based-on-time-window" tabindex="-1"><a class="header-anchor" href="#downsampling-aggregation-by-tags-based-on-time-window"><span>Downsampling Aggregation by tags based on Time Window</span></a></h3><p>Downsampling aggregation by time window is one of the most popular features in a time series database. IoTDB supports to do aggregation query by tags based on time window.</p><p>For example, a user wants to know the average temperature of the devices in each workshop, in every 5 seconds, in the range of time <code>[1000, 10000)</code>.</p><p>SQL</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">SELECT</span> <span class="token function">avg</span><span class="token punctuation">(</span>temperature<span class="token punctuation">)</span> <span class="token keyword">FROM</span> root<span class="token punctuation">.</span>factory1<span class="token punctuation">.</span><span class="token operator">*</span><span class="token operator">*</span> <span class="token keyword">GROUP</span> <span class="token keyword">BY</span> <span class="token punctuation">(</span><span class="token punctuation">[</span><span class="token number">1000</span><span class="token punctuation">,</span> <span class="token number">10000</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token number">5</span>s<span class="token punctuation">)</span><span class="token punctuation">,</span> TAGS<span class="token punctuation">(</span>city<span class="token punctuation">,</span> workshop<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>The results</p><div class="language-text line-numbers-mode" data-ext="text" data-title="text"><pre class="language-text"><code>+-----------------------------+--------+--------+------------------+ |
| | Time| city|workshop| avg(temperature)| |
| +-----------------------------+--------+--------+------------------+ |
| |1970-01-01T08:00:01.000+08:00| NULL| NULL| 50.91999893188476| |
| |1970-01-01T08:00:01.000+08:00|Shanghai| w1|113.20000076293945| |
| |1970-01-01T08:00:01.000+08:00| Beijing| w2| 103.4| |
| |1970-01-01T08:00:01.000+08:00|Shanghai| w2| 100.1999994913737| |
| |1970-01-01T08:00:01.000+08:00| Beijing| w1|103.81666692097981| |
| |1970-01-01T08:00:06.000+08:00| NULL| NULL| 50.5| |
| |1970-01-01T08:00:06.000+08:00|Shanghai| w1| 112.6500015258789| |
| |1970-01-01T08:00:06.000+08:00| Beijing| w2| 106.9000015258789| |
| |1970-01-01T08:00:06.000+08:00|Shanghai| w2| 99.80000305175781| |
| |1970-01-01T08:00:06.000+08:00| Beijing| w1| 103.5| |
| +-----------------------------+--------+--------+------------------+ |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>Comparing to the pure tag aggregations, this kind of aggregation will divide the data according to the time window specification firstly, and do the aggregation query by the multiple tags in each time window secondly.<br> The result set will also contain a time column, which have the same meaning with the time column of the result in downsampling aggregation query by time window.</p><h3 id="limitation-of-aggregation-by-tags" tabindex="-1"><a class="header-anchor" href="#limitation-of-aggregation-by-tags"><span>Limitation of Aggregation by Tags</span></a></h3><p>As this feature is still under development, some queries have not been completed yet and will be supported in the future.</p><blockquote><ol><li>Temporarily not support <code>HAVING</code> clause to filter the results.</li><li>Temporarily not support ordering by tag values.</li><li>Temporarily not support <code>LIMIT</code>，<code>OFFSET</code>，<code>SLIMIT</code>，<code>SOFFSET</code>.</li><li>Temporarily not support <code>ALIGN BY DEVICE</code>.</li><li>Temporarily not support expressions as aggregation function parameter，e.g. <code>count(s+1)</code>.</li><li>Not support the value filter, which stands the same with the <code>GROUP BY LEVEL</code> query.</li></ol></blockquote></div><!--[--><!----><!--]--><footer class="vp-page-meta"><div class="vp-meta-item edit-link"><a href="https://github.com/apache/iotdb-docs/edit/main/src/UserGuide/V1.0.x/Query-Data/Group-By.md" rel="noopener noreferrer" target="_blank" aria-label="Found Error? Edit this page on GitHub" class="nav-link vp-meta-label"><!--[--><svg xmlns="http://www.w3.org/2000/svg" class="icon edit-icon" viewBox="0 0 1024 1024" fill="currentColor" aria-label="edit icon"><path d="M430.818 653.65a60.46 60.46 0 0 1-50.96-93.281l71.69-114.012 7.773-10.365L816.038 80.138A60.46 60.46 0 0 1 859.225 62a60.46 60.46 0 0 1 43.186 18.138l43.186 43.186a60.46 60.46 0 0 1 0 86.373L588.879 565.55l-8.637 8.637-117.466 68.234a60.46 60.46 0 0 1-31.958 11.229z"></path><path d="M728.802 962H252.891A190.883 190.883 0 0 1 62.008 771.98V296.934a190.883 190.883 0 0 1 190.883-192.61h267.754a60.46 60.46 0 0 1 0 120.92H252.891a69.962 69.962 0 0 0-69.098 69.099V771.98a69.962 69.962 0 0 0 69.098 69.098h475.911A69.962 69.962 0 0 0 797.9 771.98V503.363a60.46 60.46 0 1 1 120.922 0V771.98A190.883 190.883 0 0 1 728.802 962z"></path></svg><!--]-->Found Error? Edit this page on GitHub<span><svg class="external-link-icon" 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"><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="external-link-icon-sr-only">open in new window</span></span><!----></a></div><div class="vp-meta-item git-info"><div class="update-time"><span class="vp-meta-label">Last update: </span><!----></div><!----></div></footer><nav class="vp-page-nav"><a class="route-link nav-link prev" href="/UserGuide/V1.0.x/Query-Data/Where-Condition.html" aria-label="Where Condition"><div class="hint"><span class="arrow start"></span>Prev</div><div class="link"><!---->Where Condition</div></a><a class="route-link nav-link next" href="/UserGuide/V1.0.x/Query-Data/Having-Condition.html" aria-label="Having Condition"><div class="hint">Next<span class="arrow end"></span></div><div class="link">Having Condition<!----></div></a></nav><!----><!--[--><!----><!--]--><!--]--></main><!--]--><footer style="padding-bottom:2rem;"><span id="doc-version" style="display:none;">rel/1.0</span><p style="text-align:center;color:#909399;font-size:12px;margin:0 30px;">Copyright © 2024 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:#909399;font-size:12px;margin:0 30px;"><strong>Have a question?</strong> Connect with us on QQ, WeChat, or Slack. <a href="https://github.com/apache/iotdb/issues/1995">Join the community</a> now.</p></footer></div><!--]--><!--]--><!--[--><!----><!--]--><!--]--></div> |
| <script type="module" src="/assets/app-DrPcRZG6.js" defer></script> |
| </body> |
| </html> |
