Question

我正在寻找具有已注册和未注册用户的所有组。我试图使用Group By，但是我缺少了一些东西。谢谢

Select U.IsRegistered, UG.UserGroupId
From tblGroup G
Join tblUserGroup UG on UG.GroupId = G.GroupId
Join tblUser U on U.UserId = UG.GroupId
Group By U.IsRegistered, UG.UserGroupId

tblUser
-------+----------+-------------
UserId | UserName | IsRegistered
1      | Bob      | 1
2      | Sally    | 0
3      | Jeff     | 1


tblGroup
--------+----------
GroupId | GroupName
1       | Blue
2       | Green


tblUserGroup
------------+---------+-------
UserGroupId | GroupId | UserId
1           | 1       | 1
2           | 1       | 2
3           | 2       | 3

Answer 1

您可以使用group by和having进行此操作：

Select U.IsRegistered, UG.UserGroupId
From tblUserGroup UG Join
     tblUser U
     on U.UserId = UG.GroupId
Group By UG.UserGroupId
Having sum(IsRegistered) > 0 and sum(1 - IsRegistered) > 0;

having子句仅指定至少有一个注册用户和一个非注册用户。

请注意，查询中不需要tblGroup。

Answer 2

SELECT GroupName
From tblGroup G
Join tblUserGroup UG on UG.GroupId = G.GroupId
Join tblUser U on U.UserId = UG.UserID
GROUP BY GroupName
HAVING AVG(cast(IsRegistered as float)) < 1
AND AVG(cast(IsRegistered as float)) > 0

Answer 3

如果我正确地理解了这一点，则需要满足两个条件。首先，我们需要知道该组具有未注册的用户。其次，我们需要知道该组有一个注册用户。因此，如果我们创建一个具有第一个条件的语句，并将其与具有第二个条件的语句进行内部连接，那将只剩下所需的组。

Select UnRegistered_Group.UserGroupId
From (
    SELECT UG.UserGroupID
    FROM tblGroup G
    INNER Join tblUserGroup UG on UG.GroupId = G.GroupId
    INNER Join tblUser U on U.UserId = UG.GroupId
    WHERE U.IsRegistered = 0
) AS UnRegistered_Group
Inner Join (
    SELECT UG.UserGroupID
    FROM tblGroup G
    INNER Join tblUserGroup UG on UG.GroupId = G.GroupId
    INNER Join tblUser U on U.UserId = UG.GroupId
    WHERE U.IsRegistered = 1
) AS Registered_Group
On UnRegistered_Group.UserGroupID = Registered_Group.UserGroupID;

SQL分组依据？需要子选择吗？

3 个答案: