mysql向上,向下,四舍五入取整函数

其中ceil为向上取整，round为四舍五入取整，floor为向下取整。

mysql> select ceil(2.44),round(2.44),floor(2.44);
+------------+-------------+-------------+
| ceil(2.44) | round(2.44) | floor(2.44) |
+------------+-------------+-------------+
|          3 |           2 |           2 |
+------------+-------------+-------------+
1 row in set (0.00 sec)

mysql> select ceil(2.55),round(2.55),floor(2.55);
+------------+-------------+-------------+
| ceil(2.55) | round(2.55) | floor(2.55) |
+------------+-------------+-------------+
|          3 |           3 |           2 |
+------------+-------------+-------------+
1 row in set (0.00 sec)