如何創建temp col？ MySQL查詢

Question

如何正確運行此查詢：

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

我想創建變量SUM1和其他功能使用它！

Answer 1

使用子查詢別名表達式：

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