-

运算符说明

- 为负号运算符。负号运算符将表达式的符号从正数反转为负数，反之亦然。

语法结构

1. > SELECT -column1, -column2, ...
2. FROM table_name;

示例

1. mysql> select -2;
2. +------+
3. | -2   |
4. +------+
5. |   -2 |
6. +------+

1. create table t2(c1 int, c2 int);
2. insert into t2 values (-3, 2);
3. insert into t2 values (1, 2);

5. mysql> select -c1 from t2;
6. +------+
7. | -c1  |
8. +------+
9. |    3 |
10. |   -1 |
11. +------+
12. 2 rows in set (0.00 sec)