匿名通过本文主要向大家介绍了MySQL，数值运算符，函数等相关知识,希望本文的分享对您有所帮助
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)
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