对于普通加减法运算，此处不予详细讲解，如下例：
mysql> select 3+4; +-----+ | 3+4 | +-----+ | 7 | +-----+ 1 row in set (0.03 sec)
ceil和floor
ceil为向上取整，只要有小数位，不管是几，直接入一位。例如：
mysql> select ceil(3.01); +------------+ | ceil(3.01) | +------------+ | 4 | +------------+ 1 row in set (0.02 sec)
floor与此
相反
mysql> select floor(3.99); +-------------+ | floor(3.99) | +-------------+ | 3 | +-------------+ 1 row in set (0.00 sec）
p和mod
p为取整，mod为取余
mysql> select 3/4; +--------+ | 3/4 | +--------+ | 0.7500 | +--------+ 1 row in set (0.00 sec) mysql> select 3 p 4; +---------+ | 3 p 4 | +---------+ | 0 | +---------+ 1 row in set (0.00 sec) mysql> select 3 mod 4; +---------+ | 3 mod 4 | +---------+ | 3 | +---------+ 1 row in set (0.00 sec)
注：mod可以换成％
power幂运算
例如3的2次方
mysql> select power(3,2); +------------+ | power(3,2) | +------------+ | 9 | +------------+ 1 row in set (0.14 sec)
round四舍五入
例如3.652保留小数点后两位。
mysql> select round(3.652,2); +----------------+ | round(3.652,2) | +----------------+ | 3.65 | +----------------+ 1 row in set (0.00 sec)
保留小数点后一位：
mysql> select round(3.652,1); +----------------+ | round(3.652,1) | +----------------+ | 3.7 | +----------------+ 1 row in set (0.00 sec)
truncate
直接去掉某几位
mysql> select truncate(125.89,2); +--------------------+ | truncate(125.89,2) | +--------------------+ | 125.89 | +--------------------+ 1 row in set (0.00 sec) mysql> select truncate(125.89,1); +--------------------+ | truncate(125.89,1) | +--------------------+ | 125.8 | +--------------------+ 1 row in set (0.00 sec) mysql> select truncate(125.89,0); +--------------------+ | truncate(125.89,0) | +--------------------+ | 125 | +--------------------+ 1 row in set (0.00 sec) mysql> select truncate(125.89,-1); +---------------------+ | truncate(125.89,-1) | +---------------------+ | 120 | +---------------------+ 1 row in set (0.00 sec)
以上就是mysql数值运算符和函数的内容。