mysql cos() 函数

mysql> select cos(PI()/);
+--------------------+
| cos(PI()/)        |
+--------------------+
| 0.5000000000000001 |
+--------------------+
 row in set (0.00 sec)

//获取pi

mysql> select pi();
+----------+
| pi()     |
+----------+
| 3.141593 |
+----------+
 row in set (0.00 sec)