跳至主要內容

比较运算符和函数

大约 5 分钟

比较运算符和函数

基本比较运算符

  • 输入数据类型: INT32, INT64, FLOAT, DOUBLE
  • 注意:会将所有数据转换为DOUBLE类型后进行比较。==!=可以直接比较两个BOOLEAN
  • 返回类型:BOOLEAN
运算符含义
>大于
>=大于等于
<小于
<=小于等于
==等于
!= / <>不等于

示例:

select a, b, a > 10, a <= b, !(a <= b), a > 10 && a > b from root.test;

运行结果

IoTDB> select a, b, a > 10, a <= b, !(a <= b), a > 10 && a > b from root.test;
+-----------------------------+-----------+-----------+----------------+--------------------------+---------------------------+------------------------------------------------+
|                         Time|root.test.a|root.test.b|root.test.a > 10|root.test.a <= root.test.b|!root.test.a <= root.test.b|(root.test.a > 10) & (root.test.a > root.test.b)|
+-----------------------------+-----------+-----------+----------------+--------------------------+---------------------------+------------------------------------------------+
|1970-01-01T08:00:00.001+08:00|         23|       10.0|            true|                     false|                       true|                                            true|
|1970-01-01T08:00:00.002+08:00|         33|       21.0|            true|                     false|                       true|                                            true|
|1970-01-01T08:00:00.004+08:00|         13|       15.0|            true|                      true|                      false|                                           false|
|1970-01-01T08:00:00.005+08:00|         26|        0.0|            true|                     false|                       true|                                            true|
|1970-01-01T08:00:00.008+08:00|          1|       22.0|           false|                      true|                      false|                                           false|
|1970-01-01T08:00:00.010+08:00|         23|       12.0|            true|                     false|                       true|                                            true|
+-----------------------------+-----------+-----------+----------------+--------------------------+---------------------------+------------------------------------------------+

BETWEEN ... AND ... 运算符

运算符含义
BETWEEN ... AND ...在指定范围内
NOT BETWEEN ... AND ...不在指定范围内

示例: 选择区间 [36.5,40] 内或之外的数据:

select temperature from root.sg1.d1 where temperature between 36.5 and 40;
select temperature from root.sg1.d1 where temperature not between 36.5 and 40;

模糊匹配运算符

对于 TEXT 类型的数据,支持使用 LikeRegexp 运算符对数据进行模糊匹配

运算符含义
LIKE匹配简单模式
NOT LIKE无法匹配简单模式
REGEXP匹配正则表达式
NOT REGEXP无法匹配正则表达式

输入数据类型:TEXT

返回类型:BOOLEAN

使用 Like 进行模糊匹配

匹配规则:

  • % 表示任意0个或多个字符。
  • _ 表示任意单个字符。

示例 1: 查询 root.sg.d1value 含有'cc'的数据。

IoTDB> select * from root.sg.d1 where value like '%cc%'
+-----------------------------+----------------+
|                         Time|root.sg.d1.value|
+-----------------------------+----------------+
|2017-11-01T00:00:00.000+08:00|        aabbccdd| 
|2017-11-01T00:00:01.000+08:00|              cc|
+-----------------------------+----------------+
Total line number = 2
It costs 0.002s

示例 2: 查询 root.sg.d1value 中间为 'b'、前后为任意单个字符的数据。

IoTDB> select * from root.sg.device where value like '_b_'
+-----------------------------+----------------+
|                         Time|root.sg.d1.value|
+-----------------------------+----------------+
|2017-11-01T00:00:02.000+08:00|             abc| 
+-----------------------------+----------------+
Total line number = 1
It costs 0.002s

使用 Regexp 进行模糊匹配

需要传入的过滤条件为 Java 标准库风格的正则表达式

常见的正则匹配举例:

长度为3-20的所有字符:^.{3,20}$
大写英文字符:^[A-Z]+$
数字和英文字符:^[A-Za-z0-9]+$
以a开头的:^a.*

示例 1: 查询 root.sg.d1 下 value 值为26个英文字符组成的字符串。

IoTDB> select * from root.sg.d1 where value regexp '^[A-Za-z]+$'
+-----------------------------+----------------+
|                         Time|root.sg.d1.value|
+-----------------------------+----------------+
|2017-11-01T00:00:00.000+08:00|        aabbccdd| 
|2017-11-01T00:00:01.000+08:00|              cc|
+-----------------------------+----------------+
Total line number = 2
It costs 0.002s

示例 2: 查询 root.sg.d1 下 value 值为26个小写英文字符组成的字符串且时间大于100的。

IoTDB> select * from root.sg.d1 where value regexp '^[a-z]+$' and time > 100
+-----------------------------+----------------+
|                         Time|root.sg.d1.value|
+-----------------------------+----------------+
|2017-11-01T00:00:00.000+08:00|        aabbccdd| 
|2017-11-01T00:00:01.000+08:00|              cc|
+-----------------------------+----------------+
Total line number = 2
It costs 0.002s

示例 3:

select b, b like '1%', b regexp '[0-2]' from root.test;

运行结果

+-----------------------------+-----------+-------------------------+--------------------------+
|                         Time|root.test.b|root.test.b LIKE '^1.*?$'|root.test.b REGEXP '[0-2]'|
+-----------------------------+-----------+-------------------------+--------------------------+
|1970-01-01T08:00:00.001+08:00| 111test111|                     true|                      true|
|1970-01-01T08:00:00.003+08:00| 333test333|                    false|                     false|
+-----------------------------+-----------+-------------------------+--------------------------+

IS NULL 运算符

运算符含义
IS NULL是空值
IS NOT NULL不是空值

示例 1: 选择值为空的数据:

select code from root.sg1.d1 where temperature is null;

示例 2: 选择值为非空的数据:

select code from root.sg1.d1 where temperature is not null;

IN 运算符

运算符含义
IN / CONTAINS是指定列表中的值
NOT IN / NOT CONTAINS不是指定列表中的值

输入数据类型:All Types

返回类型 BOOLEAN

注意:请确保集合中的值可以被转为输入数据的类型。

例如:

s1 in (1, 2, 3, 'test')s1的数据类型是INT32

我们将会抛出异常,因为'test'不能被转为INT32类型

示例 1: 选择值在特定范围内的数据:

select code from root.sg1.d1 where code in ('200', '300', '400', '500');

示例 2: 选择值在特定范围外的数据:

select code from root.sg1.d1 where code not in ('200', '300', '400', '500');

示例 3:

select a, a in (1, 2) from root.test;

输出2:

+-----------------------------+-----------+--------------------+
|                         Time|root.test.a|root.test.a IN (1,2)|
+-----------------------------+-----------+--------------------+
|1970-01-01T08:00:00.001+08:00|          1|                true|
|1970-01-01T08:00:00.003+08:00|          3|               false|
+-----------------------------+-----------+--------------------+

条件函数

条件函数针对每个数据点进行条件判断,返回布尔值。

函数名可接收的输入序列类型必要的属性参数输出序列类型功能类型
ON_OFFINT32 / INT64 / FLOAT / DOUBLEthreshold:DOUBLE类型BOOLEAN 类型返回ts_value >= threshold的bool值
IN_RANGEINT32 / INT64 / FLOAT / DOUBLElower:DOUBLE类型
upper:DOUBLE类型
BOOLEAN类型返回ts_value >= lower && ts_value <= upper的bool值

测试数据:

IoTDB> select ts from root.test;
+-----------------------------+------------+
|                         Time|root.test.ts|
+-----------------------------+------------+
|1970-01-01T08:00:00.001+08:00|           1|
|1970-01-01T08:00:00.002+08:00|           2|
|1970-01-01T08:00:00.003+08:00|           3|
|1970-01-01T08:00:00.004+08:00|           4|
+-----------------------------+------------+

示例 1:

SQL语句:

select ts, on_off(ts, 'threshold'='2') from root.test;

输出:

IoTDB> select ts, on_off(ts, 'threshold'='2') from root.test;
+-----------------------------+------------+-------------------------------------+
|                         Time|root.test.ts|on_off(root.test.ts, "threshold"="2")|
+-----------------------------+------------+-------------------------------------+
|1970-01-01T08:00:00.001+08:00|           1|                                false|
|1970-01-01T08:00:00.002+08:00|           2|                                 true|
|1970-01-01T08:00:00.003+08:00|           3|                                 true|
|1970-01-01T08:00:00.004+08:00|           4|                                 true|
+-----------------------------+------------+-------------------------------------+

示例 2:

Sql语句:

select ts, in_range(ts, 'lower'='2', 'upper'='3.1') from root.test;

输出:

IoTDB> select ts, in_range(ts, 'lower'='2', 'upper'='3.1') from root.test;
+-----------------------------+------------+--------------------------------------------------+
|                         Time|root.test.ts|in_range(root.test.ts, "lower"="2", "upper"="3.1")|
+-----------------------------+------------+--------------------------------------------------+
|1970-01-01T08:00:00.001+08:00|           1|                                             false|
|1970-01-01T08:00:00.002+08:00|           2|                                              true|
|1970-01-01T08:00:00.003+08:00|           3|                                              true|
|1970-01-01T08:00:00.004+08:00|           4|                                             false|
+-----------------------------+------------+--------------------------------------------------+

Copyright © 2024 The Apache Software Foundation.
Apache and the Apache feather logo are trademarks of The Apache Software Foundation

Have a question? Connect with us on QQ, WeChat, or Slack. Join the community now.

We use Google Analytics to collect anonymous, aggregated usage information.