mysql 取整数或小数或精确位数

select cast(19.16558 as decimal(9,2))#精确到几位

select round(123.5); #四舍五入

select floor(123.5);#取整数部分

select ceil(123.5);#四舍五入

参考：

https://blog.csdn.net/qq_37107280/article/details/77542127

https://blog.csdn.net/weixin_29082969/article/details/84070492

https://www.cnblogs.com/liuqianli/p/8493640.html

https://www.cnblogs.com/xiaomai333/p/7647381.html