如何创建临时col？ mysql查询

Question

如何正确运行此查询：

SELECT 
sum(1+1) as sum1,
sum(sum1 + 2) as sum2

我想创建变量sum1并在其他函数中使用它！

Answer 1

使用子查询来表示别名：

select  sum1
,       sum(sum1 + 2) as sum2
from    (
        select  sum(1+1) as sum1
        ) as SubQueryAlias