(window.webpackJsonp=window.webpackJsonp||[]).push([[783],{1180:function(s,t,a){"use strict";a.r(t);var n=a(29),e=Object(n.a)({},(function(){var s=this,t=s._self._c;return t("ContentSlotsDistributor",{attrs:{"slot-key":s.$parent.slotKey}},[t("h1",{attrs:{id:"语法约定"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#语法约定"}},[s._v("#")]),s._v(" 语法约定")]),s._v(" "),t("h2",{attrs:{id:"字面值常量"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#字面值常量"}},[s._v("#")]),s._v(" 字面值常量")]),s._v(" "),t("p",[s._v("该部分对 IoTDB 中支持的字面值常量进行说明，包括字符串常量、数值型常量、时间戳常量、布尔型常量和空值。")]),s._v(" "),t("h3",{attrs:{id:"字符串常量"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#字符串常量"}},[s._v("#")]),s._v(" 字符串常量")]),s._v(" "),t("p",[s._v("字符串是由单引号（"),t("code",[s._v("'")]),s._v("）或双引号（"),t("code",[s._v('"')]),s._v("）字符括起来的字符序列。示例如下：")]),s._v(" "),t("div",{staticClass:"language-js line-numbers-mode"},[t("pre",{pre:!0,attrs:{class:"language-js"}},[t("code",[t("span",{pre:!0,attrs:{class:"token string"}},[s._v("'a 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punctuation"}},[s._v(".")]),s._v("b"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token identifier"}},[t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("`")]),s._v("s1+s2/s3"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("`")])]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),s._v("c "),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("WITH")]),s._v(" DATATYPE"),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("=")]),s._v("INT32"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v(" ENCODING"),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("=")]),s._v("RLE\n"),t("span",{pre:!0,attrs:{class:"token comment"}},[s._v("// root.a.b.`s1+s2/s3`.c 将被解析为 Path[root, a, b, s1+s2/s3, c]")]),s._v("\n")])]),s._v(" 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具有特定含义的词，不能直接用于标识符或路径节点名，需要使用反引号进行转义。保留字是关键字的一个子集，保留字不能用于标识符或路径节点名（即使进行了转义）。")]),s._v(" "),t("p",[s._v("关于 IoTDB 的关键字和保留字列表，可以查看 "),t("RouterLink",{attrs:{to:"/zh/UserGuide/V0.13.x/Reference/Keywords.html"}},[s._v("关键字和保留字")]),s._v(" 。")],1),s._v(" "),t("h2",{attrs:{id:"表达式"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#表达式"}},[s._v("#")]),s._v(" 表达式")]),s._v(" "),t("p",[s._v("IoTDB 支持在 "),t("code",[s._v("select")]),s._v(" 子句中执行由数字常量、时间序列、算数运算表达式和时间序列生成函数（包括用户自定义函数）组成的任意嵌套表达式。")]),s._v(" "),t("p",[s._v("注意：当参与表达式的路径节点名由纯数字、单引号、或双引号组成（不推荐！）时，必须使用反引号（`）括起，以免引起歧义。示例如下：")]),s._v(" "),t("div",{staticClass:"language-sql line-numbers-mode"},[t("pre",{pre:!0,attrs:{class:"language-sql"}},[t("code",[t("span",{pre:!0,attrs:{class:"token comment"}},[s._v("-- 存在时间序列： root.sg.d.0, root.sg.d.'a' 和 root.sg.\"d\".b")]),s._v("\n"),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("select")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token number"}},[s._v("0")]),s._v(" 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"),t("h3",{attrs:{id:"反引号"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#反引号"}},[s._v("#")]),s._v(" 反引号（`）")]),s._v(" "),t("p",[s._v("反引号的使用场景如下：")]),s._v(" "),t("ol",[t("li",[s._v("在标识符中使用特殊字符时，标识符需要使用反引号括起。")]),s._v(" "),t("li",[s._v("在路径节点名中使用除路径分隔符之外的特殊字符时，路径节点名需要使用反引号括起。在这种情况下，反引号不会被系统视为节点名的一部分。")])]),s._v(" "),t("h3",{attrs:{id:"反斜杠"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#反斜杠"}},[s._v("#")]),s._v(" 反斜杠（\\）")]),s._v(" "),t("p",[s._v("反斜杠的使用场景如下：")]),s._v(" "),t("ul",[t("li",[s._v("在字符串常量中，出现双引号或单引号时，要使用反斜杠进行转义。\n"),t("ul",[t("li",[s._v("如：\"str\\\"ing\" 解析为 str\"ing、'str\\'ing' 解析为 str'ing。")])])]),s._v(" "),t("li",[s._v("在标识符中，出现反引号时，要使用反斜杠进行转义。\n"),t("ul",[t("li",[s._v("如：`na\\`me` 解析为 na`me。")])])]),s._v(" "),t("li",[s._v("在路径节点名中，出现双引号或单引号时，要使用反斜杠进行转义。注意，为了避免歧义，反斜杠会被系统视为节点名的一部分。\n"),t("ul",[t("li",[s._v("如：root.sg1.d1.\"a\\\"b\" 解析为 Path[root, sg1, d1, \"a\\\"b\"]、root.sg1.d1.'a\\'b' 解析为 Path[root, sg1, d1, 'a\\'b']、root.sg1.d1.`a\\\"b` 解析为 Path[root, sg1, 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