ACOS

声明

ACOS(X)

说明

返回 X 的反余弦值，即余弦为 X 的值。如果 X 的取值不在 [-1,1] 区间内，该函数返回 NULL。

示例

SELECT ACOS(-10), ACOS(0), ACOS(10), ACOS(-0.5), ACOS(0.5);
+-----------+--------------------+----------+--------------------+--------------------+
| ACOS(-10) | ACOS(0)            | ACOS(10) | ACOS(-0.5)         | ACOS(0.5)          |
+-----------+--------------------+----------+--------------------+--------------------+
|      NULL | 1.5707963267948966 |     NULL | 2.0943951023931957 | 1.0471975511965979 |
+-----------+--------------------+----------+--------------------+--------------------+
1 row in set (0.001 sec)