SELECT
round(52.45, 0) AS round4,
round(52.54, 0) AS round5,
round(52.45, 1) AS round41,
round(52.54, 1) AS round51,
floor(52.4) AS floor4,
floor(52.5) AS floor5,
ceiling(52.4) AS ceiling4,
ceiling(52.5) AS ceiling5
round是四舍五入
floor是向下取整
ceiling 是向上取整
round需要一个位数的参数
floor和ceiling都取到整数，不含小数。
原文：https://www.cnblogs.com/jackadam/p/9749331.html