#演示数学相关函数
#1.ABS(num)：绝对值
SELECT ABS(-10) FROM DUAL;
#2.BIN(num)：十进制转二进制
SELECT BIN(10) FROM DUAL;
#3.CEILING(num)：向上取整，得到比num大的最小整数
SELECT CEILING(-10.25) FROM DUAL;
#4.FLOOR(num)：向下取整，得到比num小的最大整数
SELECT FLOOR(-10.23) FROM DUAL;
#5.CONV(num,from_base,to_base)：进制转换
SELECT CONV(10,2,10) FROM DUAL;
#6.FORMAT(num,decimal_places)：保留小数位数（四舍五入）
SELECT FORMAT(-10.264245,5) FROM DUAL;
#7.HEX(DecimalNumber)：转十六进制
SELECT HEX(31) FROM DUAL;
#8.least(num1,num2...)：求最小值
SELECT LEAST(10,20,12,25) FROM DUAL;
#9.MOD(numerator,denominator)：求余
SELECT MOD(10,3) FROM DUAL;
#10.RAND([seed])：返回随机数，其范围为0-1.0,如果添加seed，seed不变则随即数不变
SELECT RAND(5) FROM DUAL;
SELECT RAND(5) FROM DUAL;