import{_ as e,o as a,c as i,a as t,f as n}from"./app-d4806199.js";const l={},d=n(`<h1 id="常用sql语句" tabindex="-1"><a class="header-anchor" href="#常用sql语句" aria-hidden="true">#</a> 常用SQL语句</h1><h2 id="数据库管理" tabindex="-1"><a class="header-anchor" href="#数据库管理" aria-hidden="true">#</a> 数据库管理</h2><p>数据库（Database）类似关系数据库中的 Database，是一组结构化的时序数据的集合。</p><ul><li>创建数据库</li></ul><p>创建一个名为 root.ln 的数据库,语法如下：</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>CREATE DATABASE root.ln
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><ul><li>查看数据库</li></ul><p>查看所有数据库：</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>SHOW DATABASES
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><ul><li>删除数据库</li></ul><p>删除名为 root.ln 的数据库：</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>DELETE DATABASE root.ln
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><ul><li>统计数据库数量</li></ul><p>统计数据库的总数</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>COUNT DATABASES
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><h2 id="时间序列管理" tabindex="-1"><a class="header-anchor" href="#时间序列管理" aria-hidden="true">#</a> 时间序列管理</h2><p>时间序列（Timeseries）是以时间为索引的数据点的集合，在IoTDB中时间序列指的是一个测点的完整序列，本节主要介绍时间序列的管理方式。</p><ul><li>创建时间序列</li></ul><p>需指定编码方式与数据类型。例如创建一条名为root.ln.wf01.wt01.temperature的时间序列：</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>CREATE TIMESERIES root.ln.wf01.wt01.temperature WITH datatype=FLOAT,ENCODING=RLE
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><ul><li>查看时间序列</li></ul><p>查看所有时间序列：</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>SHOW TIMESERIES
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>使用通配符匹配数据库root.ln下的时间序列：</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>SHOW TIMESERIES root.ln.**
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><ul><li>删除时间序列</li></ul><p>创建名为 root.ln.wf01.wt01.temperature 的时间序列</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>DELETE TIMESERIES root.ln.wf01.wt01.temperature
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><ul><li>统计时间序列</li></ul><p>统计时间序列的总数</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>COUNT TIMESERIES root.**
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>统计某通配符路径下的时间序列数量：</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>COUNT TIMESERIES root.ln.**
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><h2 id="时间序列路径管理" tabindex="-1"><a class="header-anchor" href="#时间序列路径管理" aria-hidden="true">#</a> 时间序列路径管理</h2><p>除时间序列概念外，IoTDB中还有子路径、设备的概念。</p><p>**子路径：**是一条完整时间序列名称中的一部分路径，如时间序列名称为root.ln.wf01.wt01.temperature，则root.ln、root.ln.wf01、root.ln.wf01.wt01都是其子路径。</p><p>**设备：**是一组时间序列的组合，在 IoTDB 中设备是由root至倒数第二级节点的子路径，如时间序列名称为root.ln.wf01.wt01.temperature，则root.ln.wf01.wt01是其设备</p><ul><li>查看设备</li></ul><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>SHOW DEVICES
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><ul><li>查看子路径</li></ul><p>查看 root.ln 的下一层：</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>SHOW CHILD PATHS root.ln
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><ul><li>查看子节点</li></ul><p>查看 root.ln 的下一层：</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>SHOW CHILD NODES root.ln
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><ul><li>统计设备数量</li></ul><p>统计所有设备</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>COUNT DEVICES
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><ul><li>统计节点数</li></ul><p>统计路径中指定层级的节点个数</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>COUNT NODES root.ln.** LEVEL=2
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><h2 id="查询数据" tabindex="-1"><a class="header-anchor" href="#查询数据" aria-hidden="true">#</a> 查询数据</h2><p>以下为IoTDB中常用查询语句。</p><ul><li>查询指定时间序列的数据</li></ul><p>查询root.ln.wf01.wt01设备下的所有时间序列的数据</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>SELECT * FROM root.ln.wf01.wt01
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><ul><li>查询某时间范围内的时间序列数据</li></ul><p>查询root.ln.wf01.wt01.temperature时间序列中时间戳大于 2022-01-01T00:05:00.000 的数据</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>SELECT temperature FROM root.ln.wf01.wt01 WHERE time &gt; 2022-01-01T00:05:00.000
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><ul><li>查询数值在指定范围内的时间序列数据</li></ul><p>查询root.ln.wf01.wt01.temperature时间序列中数值大于 36.5 的数据：</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>SELECT temperature FROM root.ln.wf01.wt01 WHERE temperature &gt; 36.5
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><ul><li>使用 last 查询最新点数据</li></ul><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>SELECT last * FROM root.ln.wf01.wt01
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div>`,64);function r(s,u){return a(),i("div",null,[t(`

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`),d])}const c=e(l,[["render",r],["__file","General-SQL-Statements.html.vue"]]);export{c as default};