concat

description

Syntax

VARCHAR concat(VARCHAR,...)

将多个字符串连接起来, 如果参数中任意一个值是 NULL，那么返回的结果就是 NULL

example

1. mysql> select concat("a", "b");
2. +------------------+
3. | concat('a', 'b') |
4. +------------------+
5. | ab               |
6. +------------------+

8. mysql> select concat("a", "b", "c");
9. +-----------------------+
10. | concat('a', 'b', 'c') |
11. +-----------------------+
12. | abc                   |
13. +-----------------------+

15. mysql> select concat("a", null, "c");
16. +------------------------+
17. | concat('a', NULL, 'c') |
18. +------------------------+
19. | NULL                   |
20. +------------------------+

keyword

CONCAT