2020-06-03 阅读量: 1633
数学函数
ABS(n)
返回n的绝对值
示例
FLOOR(n)
返回不大于n的最大整数值
示例
mysql> select reverse('CDA');
+----------------+
| reverse('CDA') |
+----------------+
| ADC |
+----------------+
mysql> select upper('cda');
+--------------+
| upper('cda') |
+--------------+
| CDA |
+--------------+
mysql> select lower('CDA');
+-----------------+
| lower('CDA') |+-------------- --+| cda |
+-----------------+
mysql> select abs(-32);
+----------+
| abs(-32) |
+----------+
| 32 |
+----------+
CEILING(n)
返回不小于n的最小整数值
示例
ROUND(n[,d])
返回n的四舍五入值,保留d位小数(d的默认值为0)
示例
RAND([n])
返回在范围0到1.0内的随机浮点值(可以使用数字n作为初始值)
示例
时期时间函数
DATE(date)
返回指定日期/时间表达式的日期部分或将文本转为日期格式
mysql> select floor(1.23);
+-------------+
| floor(1.23) |
+-------------+
| 1 |
+-------------+
mysql> select ceiling(1.23);
+---------------+
| ceiling(1.23) |
+---------------+
| 2 |
+---------------+
mysql> select round(1.58);
+-------------+
| round(1.58) |
+-------------+
| 2 |
+-------------+
mysql> select rand();
+--------------------+
| rand() |
+--------------------+
| 0.8111234054072978 |
+--------------------+
mysql> select rand(2);
+--------------------+
| rand(2) |
+--------------------+
| 0.6555866465490187 |
+--------------------+
