mysql - sql 在查询子句中使用求和结果

Question

select acc.user_id
     , member.nickname
     , sum(credit) as ttl 
     , member.balance
  from account_history as acc
  left 
  join member
    ON acc.user_id = member.user_id
 where balance > 0 
   and balance <50
 group 
    by user_id 

我想显示 ttl ( sum(credit) ) > 0 ,

所以我改成

select acc.user_id,member.nickname, sum(credit) as ttl ,member.balance
from account_history as acc left join member 
ON acc.user_id=member.user_id 
where balance > 0 and balance <50 and ttl > 0
group by user_id 

但它变成了错误。未找到列 ttl

Answer 1

使用 having 子句中的值应该有效:

select acc.user_id,member.nickname, sum(credit) as ttl ,member.balance
from account_history as acc 
    left join member ON acc.user_id=member.user_id 
where balance > 0 and balance <50 
group by user_id 
having  ttl > 0

在 where 子句中你不能使用别名

另见 https://dev.mysql.com/doc/refman/8.0/en/problems-with-alias.html