WHERE Clauses

1 Syntax Overview

WHERE booleanExpression

__WHERE clause __: Used to specify filtering conditions in SQL queries, the WHERE clause is executed immediately after the FROM clause.

2 Example Data

In the Example Data page, there are SQL statements for building the table structure and inserting data. By downloading and executing these statements in the IoTDB CLI, you can import data into IoTDB. You can use this data to test and execute the SQL statements in the examples and obtain the corresponding results.

Example 1: Select a row with a specific ID

SELECT * FROM table1 WHERE plant_id = '1001';

The execution result is as follows:

+-----------------------------+------+--------+---------+--------+-----------+-----------+--------+------+-----------------------------+
|                         time|region|plant_id|device_id|model_id|maintenance|temperature|humidity|status|                   modifytime|
+-----------------------------+------+--------+---------+--------+-----------+-----------+--------+------+-----------------------------+
|2024-11-26T13:37:00.000+08:00|  北京|    1001|      100|       A|        180|       90.0|    35.1|  true|2024-11-26T13:37:34.000+08:00|
|2024-11-26T13:38:00.000+08:00|  北京|    1001|      100|       A|        180|       90.0|    35.1|  true|2024-11-26T13:38:25.000+08:00|
|2024-11-27T16:38:00.000+08:00|  北京|    1001|      101|       B|        180|       null|    35.1|  true|2024-11-26T16:37:01.000+08:00|
|2024-11-27T16:39:00.000+08:00|  北京|    1001|      101|       B|        180|       85.0|    35.3|  null|                         null|
|2024-11-27T16:40:00.000+08:00|  北京|    1001|      101|       B|        180|       85.0|    null|  null|2024-11-26T16:37:03.000+08:00|
|2024-11-27T16:41:00.000+08:00|  北京|    1001|      101|       B|        180|       85.0|    null|  null|2024-11-26T16:37:04.000+08:00|
|2024-11-27T16:42:00.000+08:00|  北京|    1001|      101|       B|        180|       null|    35.2| false|                         null|
|2024-11-27T16:43:00.000+08:00|  北京|    1001|      101|       B|        180|       null|    null| false|                         null|
|2024-11-27T16:44:00.000+08:00|  北京|    1001|      101|       B|        180|       null|    null| false|2024-11-26T16:37:08.000+08:00|
+-----------------------------+------+--------+---------+--------+-----------+-----------+--------+------+-----------------------------+
Total line number = 9
It costs 0.091s

Example 2: Choose to use LIKE expression for matching

SELECT * FROM table1 WHERE plant_id LIKE '300%';

The execution result is as follows:

+-----------------------------+------+--------+---------+--------+-----------+-----------+--------+------+-----------------------------+
|                         time|region|plant_id|device_id|model_id|maintenance|temperature|humidity|status|                   modifytime|
+-----------------------------+------+--------+---------+--------+-----------+-----------+--------+------+-----------------------------+
|2024-11-29T11:00:00.000+08:00|  上海|    3002|      100|       E|        180|       null|    45.1|  true|                         null|
|2024-11-29T18:30:00.000+08:00|  上海|    3002|      100|       E|        180|       90.0|    35.4|  true|2024-11-29T18:30:15.000+08:00|
|2024-11-28T08:00:00.000+08:00|  上海|    3001|      100|       C|         90|       85.0|    null|  null|2024-11-28T08:00:09.000+08:00|
|2024-11-28T09:00:00.000+08:00|  上海|    3001|      100|       C|         90|       null|    40.9|  true|                         null|
|2024-11-28T10:00:00.000+08:00|  上海|    3001|      100|       C|         90|       85.0|    35.2|  null|2024-11-28T10:00:11.000+08:00|
|2024-11-28T11:00:00.000+08:00|  上海|    3001|      100|       C|         90|       88.0|    45.1|  true|2024-11-28T11:00:12.000+08:00|
|2024-11-30T09:30:00.000+08:00|  上海|    3002|      101|       F|        360|       90.0|    35.2|  true|                         null|
|2024-11-30T14:30:00.000+08:00|  上海|    3002|      101|       F|        360|       90.0|    34.8|  true|2024-11-30T14:30:17.000+08:00|
|2024-11-29T10:00:00.000+08:00|  上海|    3001|      101|       D|        360|       85.0|    null|  null|2024-11-29T10:00:13.000+08:00|
+-----------------------------+------+--------+---------+--------+-----------+-----------+--------+------+-----------------------------+
Total line number = 9
It costs 0.261s

Example 3: Choose to use composite expression filtering

SELECT * FROM table1 WHERE time >= 2024-11-28 00:00:00 and (plant_id = '3001' OR plant_id = '3002');

The execution result is as follows:

+-----------------------------+------+--------+---------+--------+-----------+-----------+--------+------+-----------------------------+
|                         time|region|plant_id|device_id|model_id|maintenance|temperature|humidity|status|                   modifytime|
+-----------------------------+------+--------+---------+--------+-----------+-----------+--------+------+-----------------------------+
|2024-11-26T13:37:00.000+08:00|  北京|    1001|      100|       A|        180|       90.0|    35.1|  true|2024-11-26T13:37:34.000+08:00|
|2024-11-26T13:38:00.000+08:00|  北京|    1001|      100|       A|        180|       90.0|    35.1|  true|2024-11-26T13:38:25.000+08:00|
|2024-11-27T16:38:00.000+08:00|  北京|    1001|      101|       B|        180|       null|    35.1|  true|2024-11-26T16:37:01.000+08:00|
|2024-11-27T16:39:00.000+08:00|  北京|    1001|      101|       B|        180|       85.0|    35.3|  null|                         null|
|2024-11-27T16:40:00.000+08:00|  北京|    1001|      101|       B|        180|       85.0|    null|  null|2024-11-26T16:37:03.000+08:00|
|2024-11-27T16:41:00.000+08:00|  北京|    1001|      101|       B|        180|       85.0|    null|  null|2024-11-26T16:37:04.000+08:00|
|2024-11-27T16:42:00.000+08:00|  北京|    1001|      101|       B|        180|       null|    35.2| false|                         null|
|2024-11-27T16:43:00.000+08:00|  北京|    1001|      101|       B|        180|       null|    null| false|                         null|
|2024-11-27T16:44:00.000+08:00|  北京|    1001|      101|       B|        180|       null|    null| false|2024-11-26T16:37:08.000+08:00|
+-----------------------------+------+--------+---------+--------+-----------+-----------+--------+------+-----------------------------+
Total line number = 9
It costs 0.091s