mysql - 大查询 SQL 中其他列中 2 个提取列的总和

Question

select x,
count(case when i='abc' then 1 else null end) as ele1,
count(case when i='def' then 1 else null end) as ele2,
sum(ele1+ele2) as sum1 from (INNER QUERY)

当我使用 sum(ele1+ele2) 时，抛出 ele1 未找到的错误。如何在不使用任何其他外部查询的情况下在同一查询中获取 sum1？

Answer 1

您不能在选择中使用别名作为列名

select x,
count(case when i='abc' then 1 else null end) as ele1,
count(case when i='def' then 1 else null end) as ele2,
sum(  ( case when i='abc' then 1 else null end  ) +  
    ( case when i='def' then 1 else null end ) ) as sum1 
from (INNER QUERY)