ifnull

description

Syntax

ifnull(expr1, expr2)

如果 expr1 的值不为 NULL 则返回 expr1，否则返回 expr2

example

1. mysql> select ifnull(1,0);
2. +--------------+
3. | ifnull(1, 0) |
4. +--------------+
5. |            1 |
6. +--------------+

8. mysql> select ifnull(null,10);
9. +------------------+
10. | ifnull(NULL, 10) |
11. +------------------+
12. |               10 |
13. +------------------+

keywords

IFNULL