ASIN() 反正弦

ASIN(X)
回傳 X 的反正弦，即，正弦為 X 的值。若 X 不在 -1 到 1 的範圍之內，則回傳 NULL 。
mysql> SELECT ASIN(0.2);
-> 0.20135792079033

mysql> SELECT ASIN('foo');
+-------------+
| ASIN('foo') |
+-------------+
| 0 |
+-------------+
1 row in set, 1 warning (0.00 sec)

mysql> SHOW WARNINGS;
+---------+------+-----------------------------------------+
| Level | Code | Message |
+---------+------+-----------------------------------------+
| Warning | 1292 | Truncated incorrect DOUBLE value: 'foo' |
+---------+------+-----------------------------------------+