#mySql的数学函数select ABS(-5); #绝对值select ceiling(-5.8); #取大整数select floor(-5.8); #取小整数select LEAST(10,3,23,40,0);#取最小数select GREATEST(1,23,4,6,9,12,9);#取最大数select MOD(10,3);#除余select PI();#π的值select RAND(2);#随机数select ROUND(10.4367,3);#四舍五入 取后面三位小数selec