*round(四舍五入)
select round(1.34) 1
select round(1.9) 2
select round(1.234,2) 1.23
select round(1.457,2) 1.46
*ceil(向上取整)
select ceil(1.34) 2
select ceil(1.00) 1
*floor(向下取整)
select floor(1.34) 1
select floo(-9.9) -10
*truncate(截断)
select truncate(1.99,1) 1.9
*mod (取余)
select mod(10,3) 1
select mod(-10,-3) -1
来源:https://www.cnblogs.com/Be-your-own-hero/p/11318210.html