ASIN(X)

ASIN()函数返回X的反正弦，X的值必须在-1到1的范围内，否则返回NULL。

SQL> SELECT ASIN(1);
+---------------------------------------------------------+
| ASIN(1)                                                 |
+---------------------------------------------------------+
| 1.5707963267949                                         |
+---------------------------------------------------------+
1 row in set (0.00 sec)