ABS (number2 ) //绝对值


BIN (decimal_number ) //十进制转二进制


CEILING (number2 ) //向上取整


CONV(number2,from_base,to_base) //进制转换


FLOOR (number2 ) //向下取整


FORMAT (number,decimal_places ) //保留小数位数


HEX (DecimalNumber ) //转十六进制


注：HEX()中可传入字符串，则返回其ASC-11码，如HEX('DEF')返回4142143


也可以传入十进制整数，返回其十六进制编码，如HEX(25)返回19


LEAST (number , number2  [,..]) //求最小值


MOD (numerator ,denominator ) //求余


POWER (number ,power ) //求指数


RAND([seed]) //随机数


ROUND (number  [,decimals ]) //四舍五入,decimals为小数位数]

注：返回类型并非均为整数，如：

(1)默认变为整形值

mysql> select round(1.23);

+-------------+

| round(1.23) |

+-------------+

|           1 |

+-------------+

1 row in set (0.00 sec)

mysql> select round(1.56);

+-------------+

| round(1.56) |

+-------------+

|           2 |

+-------------+

1 row in set (0.00 sec)

(2)可以设定小数位数，返回浮点型数据

mysql> select round(1.567,2);

+----------------+

| round(1.567,2) |

+----------------+

|           1.57 |

+----------------+

1 row in set (0.00 sec)


SIGN (number2 ) //返回符号,正负或0


SQRT(number2) //开平方