| import{_ as e,o as i,c as n,a as s,f as d}from"./app-5cdcb249.js";const a={},r=d(`<h1 id="路径结点名" tabindex="-1"><a class="header-anchor" href="#路径结点名" aria-hidden="true">#</a> 路径结点名</h1><p>路径结点名是特殊的标识符，其还可以是通配符 * 或 **。在创建时间序列时，各层级的路径结点名不能为通配符 * 或 **。在查询语句中，可以用通配符 * 或 ** 来表示路径结点名，以匹配一层或多层路径。</p><h2 id="通配符" tabindex="-1"><a class="header-anchor" href="#通配符" aria-hidden="true">#</a> 通配符</h2><p><code>*</code>在路径中表示一层。例如<code>root.vehicle.*.sensor1</code>代表的是以<code>root.vehicle</code>为前缀，以<code>sensor1</code>为后缀，层次等于 4 层的路径。</p><p><code>**</code>在路径中表示是（<code>*</code>）+，即为一层或多层<code>*</code>。例如<code>root.vehicle.device1.**</code>代表的是<code>root.vehicle.device1.*</code>, <code>root.vehicle.device1.*.*</code>, <code>root.vehicle.device1.*.*.*</code>等所有以<code>root.vehicle.device1</code>为前缀路径的大于等于 4 层的路径；<code>root.vehicle.**.sensor1</code>代表的是以<code>root.vehicle</code>为前缀，以<code>sensor1</code>为后缀，层次大于等于 4 层的路径。</p><p>由于通配符 * 在查询表达式中也可以表示乘法符号，下述例子用于帮助您区分两种情况：</p><div class="language-SQL line-numbers-mode" data-ext="SQL"><pre class="language-SQL"><code># 创建时间序列 root.sg.\`a*b\` |
| create timeseries root.sg.\`a*b\` with datatype=FLOAT,encoding=PLAIN; |
| # 请注意，如标识符部分所述，a*b包含特殊字符，需要用\`\`括起来使用 |
| # create timeseries root.sg.a*b with datatype=FLOAT,encoding=PLAIN 是错误用法 |
| |
| # 创建时间序列 root.sg.a |
| create timeseries root.sg.a with datatype=FLOAT,encoding=PLAIN; |
| |
| # 创建时间序列 root.sg.b |
| create timeseries root.sg.b with datatype=FLOAT,encoding=PLAIN; |
| |
| # 查询时间序列 root.sg.\`a*b\` |
| select \`a*b\` from root.sg |
| # 其结果集表头为 |
| |Time|root.sg.a*b| |
| |
| # 查询时间序列 root.sg.a 和 root.sg.b的乘积 |
| select a*b from root.sg |
| # 其结果集表头为 |
| |Time|root.sg.a * root.sg.b| |
| </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></div><h2 id="标识符" tabindex="-1"><a class="header-anchor" href="#标识符" aria-hidden="true">#</a> 标识符</h2><p>路径结点名不为通配符时，使用方法和标识符一致。<strong>在 SQL 中需要使用反引号引用的路径结点，在结果集中也会用反引号引起。</strong></p><p>需要使用反引号进行引用的部分特殊情况示例：</p><ul><li>创建时间序列时，如下情况需要使用反引号对特殊节点名进行引用：</li></ul><div class="language-SQL line-numbers-mode" data-ext="SQL"><pre class="language-SQL"><code># 路径结点名中包含特殊字符，时间序列各结点为["root","sg","www.\`baidu.com"] |
| create timeseries root.sg.\`www.\`\`baidu.com\`.a with datatype=FLOAT,encoding=PLAIN; |
| |
| # 路径结点名为实数 |
| create timeseries root.sg.\`111\` with datatype=FLOAT,encoding=PLAIN; |
| </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></div><p>依次执行示例中语句后，执行 show timeseries，结果如下：</p><div class="language-SQL line-numbers-mode" data-ext="SQL"><pre class="language-SQL"><code>+---------------------------+-----+-------------+--------+--------+-----------+----+----------+ |
| | timeseries|alias|database|dataType|encoding|compression|tags|attributes| |
| +---------------------------+-----+-------------+--------+--------+-----------+----+----------+ |
| | root.sg.\`111\`.a| null| root.sg| FLOAT| PLAIN| SNAPPY|null| null| |
| |root.sg.\`www.\`\`baidu.com\`.a| null| root.sg| FLOAT| PLAIN| SNAPPY|null| null| |
| +---------------------------+-----+-------------+--------+--------+-----------+----+----------+ |
| </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></div><ul><li>插入数据时，如下情况需要使用反引号对特殊节点名进行引用：</li></ul><div class="language-SQL line-numbers-mode" data-ext="SQL"><pre class="language-SQL"><code># 路径结点名中包含特殊字符 |
| insert into root.sg.\`www.\`\`baidu.com\`(timestamp, a) values(1, 2); |
| |
| # 路径结点名为实数 |
| insert into root.sg(timestamp, \`111\`) values (1, 2); |
| </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></div><ul><li>查询数据时，如下情况需要使用反引号对特殊节点名进行引用：</li></ul><div class="language-SQL line-numbers-mode" data-ext="SQL"><pre class="language-SQL"><code># 路径结点名中包含特殊字符 |
| select a from root.sg.\`www.\`\`baidu.com\`; |
| |
| # 路径结点名为实数 |
| select \`111\` from root.sg |
| </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></div><p>结果集分别为：</p><div class="language-SQL line-numbers-mode" data-ext="SQL"><pre class="language-SQL"><code># select a from root.sg.\`www.\`\`baidu.com\` 结果集 |
| +-----------------------------+---------------------------+ |
| | Time|root.sg.\`www.\`\`baidu.com\`.a| |
| +-----------------------------+---------------------------+ |
| |1970-01-01T08:00:00.001+08:00| 2.0| |
| +-----------------------------+---------------------------+ |
| |
| # select \`111\` from root.sg 结果集 |
| +-----------------------------+-------------+ |
| | Time|root.sg.\`111\`| |
| +-----------------------------+-------------+ |
| |1970-01-01T08:00:00.001+08:00| 2.0| |
| +-----------------------------+-------------+ |
| </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>`,20);function o(l,c){return i(),n("div",null,[s(` |
| |
| Licensed to the Apache Software Foundation (ASF) under one |
| or more contributor license agreements. See the NOTICE file |
| distributed with this work for additional information |
| regarding copyright ownership. The ASF licenses this file |
| to you under the Apache License, Version 2.0 (the |
| "License"); you may not use this file except in compliance |
| with the License. You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, |
| software distributed under the License is distributed on an |
| "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| KIND, either express or implied. See the License for the |
| specific language governing permissions and limitations |
| under the License. |
| |
| `),r])}const v=e(a,[["render",o],["__file","NodeName-In-Path.html.vue"]]);export{v as default}; |
