Mysql 如何在 SQL 的计算列中显示小数点后两位

发布于03月10日

 select *, 
        (TotalDeaths/TotalCases)*100 as PercentDeath, 
        (TotalDeaths/population)*100 as DeathPercentPopulation
from ( select location, 
              population, 
              sum(newcases) as TotalCases, 
              sum(newdeaths) as TotalDeaths
      from deaths
      where continent is not null
      group by location
     ) as newtable
order by DeathPercentPopulation desc

在"死亡百分比"和"死亡百分比人口"列中，小数点后有几个数字.但是我只想在小数点后显示两位数.我如何在不再次嵌套此查询的情况下做到这一点？

推荐答案

你可能需要TRUNCATE美元

截断(X，D)

返回数字X，截断为D位小数.如果D为0，则

比如:

select *, 
        TRUNCATE((TotalDeaths/TotalCases)*100,2) as PercentDeath, 
        TRUNCATE((TotalDeaths/population)*100,2) as DeathPercentPopulation
from ( select location, 
              population, 
              sum(newcases) as TotalCases, 
              sum(newdeaths) as TotalDeaths
      from deaths
      where continent is not null
      group by location
     ) as newtable
order by DeathPercentPopulation desc

或者你可以使用ROUND功能.

MySQL中的ROUND()函数用于将数字四舍五入到指定的值

语法:

ROUND(X，D)参数:此方法在

X:要四舍五入的数字.D:小数位数，最多为

select *, 
        ROUND((TotalDeaths/TotalCases)*100,2) as PercentDeath, 
        ROUND((TotalDeaths/population)*100,2) as DeathPercentPopulation
from ( select location, 
              population, 
              sum(newcases) as TotalCases, 
              sum(newdeaths) as TotalDeaths
      from deaths
      where continent is not null
      group by location
     ) as newtable
order by DeathPercentPopulation desc