mysql 在 where 子句中使用用户定义的变量

Question

sql查询:

select
    u.username,
        @total_subscribers:=(
            select count(s.id)
                from subscribers as s
                where s.suid = u.uid
        ) as total_subscribers
from users as u
where @total_subscribers > 0

如果我删除 where @total_subscribers > 0 查询将显示所有用户及其订阅者总数

但我只想显示那些至少拥有 1 个订阅者的用户...在添加 where 子句并使用定义的变量后，我得到一个空结果集。

Answer 1

您可以使用group by和having来做到这一点:

select
   u.username,
   count(s.id) as total_subscribers
from users as u
inner join subscribers as s on s.suid = u.uid
group by u.id
having count(s.id) > 0