绝对值函数ABS(x)和圆周率函数PI()
mysql> SELECT ABS(0.5), ABS(-0.5), PI();
+----------+-----------+----------+
| ABS(0.5) | ABS(-0.5) | PI() |
+----------+-----------+----------+
| 0.5 | 0.5 | 3.141593 |
+----------+-----------+----------+
row in set (0.00 sec)
平方根函数SQRT(x)和求余函数MOD(x,y)
mysql> SELECT SQRT(16), SQRT(3), MOD(13,4);
+----------+--------------------+-----------+
| SQRT(16) | SQRT(3) | MOD(13,4) |
+----------+--------------------+-----------+
| 4 | 1.7320508075688772 | 1 |
+----------+--------------------+-----------+
row in set (0.00 sec)
取整函数CEIL(x)、CEILING(x)和FLOOR(x)
mysql> SELECT CEIL(2.3), CEIL(-2.3), CEILING(2.3), CEILING(-2.3);
+-----------+------------+--------------+---------------+
| CEIL(2.3) | CEIL(-2.3) | CEILING(2.3) | CEILING(-2.3) |
+-----------+------------+--------------+---------------+
| 3 | -2 | 3 | -2 |
+-----------+------------+--------------+---------------+
row in set (0.00 sec)
mysql> SELECT FLOOR(2.3), FLOOR(-2.3);
+------------+-------------+
| FLOOR(2.3) | FLOOR(-2.3) |
+------------+-------------+
| 2 | -3 |
+------------+-------------+
row in set (0.00 sec)