IN

语法说明

IN 运算符可以在WHERE语句中指定特定的多个值，本质上是多个 OR 条件的简写。

语法结构

1. > SELECT column1, column2, ...
2. FROM table_name
3. WHERE column_name IN (value1, value2, ...);

示例

1. > create table t2(a int,b varchar(5),c float, d date, e datetime);
2. > insert into t2 values(1,'a',1.001,'2022-02-08','2022-02-08 12:00:00');
3. > insert into t2 values(2,'b',2.001,'2022-02-09','2022-02-09 12:00:00');
4. > insert into t2 values(1,'c',3.001,'2022-02-10','2022-02-10 12:00:00');
5. > insert into t2 values(4,'d',4.001,'2022-02-11','2022-02-11 12:00:00');

7. > select * from t2 where a in (2,4);
8. a   b   c   d   e
9. 2   b   2.0010  2022-02-09  2022-02-09 12:00:00
10. 4   d   4.0010  2022-02-11  2022-02-11 12:00:00

12. > select * from t2 where a not in (2,4);
13. a   b   c   d   e
14. 1   a   1.0010  2022-02-08  2022-02-08 12:00:00
15. 1   c   3.0010  2022-02-10  2022-02-10 12:00:00

17. > select * from t2 where b not in ('e',"f");
18. a   b   c   d   e
19. 1   a   1.0010  2022-02-08  2022-02-08 12:00:00
20. 2   b   2.0010  2022-02-09  2022-02-09 12:00:00
21. 1   c   3.0010  2022-02-10  2022-02-10 12:00:00
22. 4   d   4.0010  2022-02-11  2022-02-11 12:00:00

24. > select * from t2 where e not in ('2022-02-09 12:00:00') and a in (4,5);
25. a   b   c   d   e
26. 4   d   4.0010  2022-02-11  2022-02-11 12:00:00

限制

• 目前，IN 左侧只支持常数列表。
• IN 左侧只支持单列数据，不支持多列组成的元组。
• IN目前未对NULL值进行很好地处理，右侧不能使用 NULL值。