SQL HAVING未知列

Question

我正在使用WHERE XXX IN（SQL），因此（SQL）必须只选择一个列

在这种情况下，我从一个组中选择一些customer_id，而这些客户只属于该组

WHERE `id_customer` IN(
SELECT g.`id_customer` // this must select *only one* column
FROM ps_customer_group AS g
Group By g.`id_customer`
Having COUNT(g.`id_customer`) = 1
AND  g.`id_group`=3  // **- Unknown column 'g.id_group' in 'having clause'** 
)

原始数据看起来像这样，顺便说一下这不是结果

Answer 1

试试这个：

WHERE id_customer IN(

    select g.id_customer from
    ps_customer_group as g
    where g.id_group=3 -- That belongs to this group
    and g.id_customer in(

       SELECT g.id_customer
       FROM ps_customer_group AS g 
       Group By g.id_customer 
       Having COUNT(g.id_group) = 1 -- is his only group
    )

)

这是test

Answer 2

如果您想知道某个客户是否只属于一个组（ID = 3），您必须更改您的查询：

select g.id_customer
  from ps_customer_group AS g 
 where g.id_customer in (
         select id_customer 
           from ps_customer_group 
          where id_group=3
       )
 Group By g.id_customer 
Having COUNT(distinct g.id_group) = 1

这将列出属于组＃3且不属于其他组的所有客户。