从多对多关系表中取回最新记录

Question

我正在使用SQL Server 2008 R2。

我有three tables在我的数据库中有many-to-many关系如下。

TblServiceLevel  
Id ServiceLevel Code 
1 C    1 
2 R    1 
3 V    1 
4 R Test   4 
5 C Test   4 
6 S    2 
7 K    3 


TblUser 
Id Name 
1 A 
2 B 
3 C 
4 D 
5 E 
6 F 


TblUserServiceLevel   
Id UserId ServiceLevelId Status 
1 1  1    Active 
2 1  1    Deactive 
3 2  3    Active 
4 3  4    Active 
5 1  5    Active 
6 5  1    Active 
7 2  3    Deactive 
8 3  4    Deactive 
9 5  1    Deactive 
10 2  3    Active 
11 3  4    Active 
12 4  1    Active 

现在，

从这个表，我想是不同用户存在于TblUserServiceLevel和 有latest service level ="Active"和ServiceLevel.Code <> 4.

谁能帮助我？

结果是2和4用户ID。

Answer 1

select t1.UserId 
from TblUserServiceLevel t1 
inner join (
    select UserId, max (Id) as maxId 
    from TblUserServiceLevel 
    group by UserId 
) t2 on t1.UserId = t2.UserId and t1.Id = t2.maxId 
inner join TblServiceLevel sl on t1.ServiceLevelId = sl.Id and sl.Code <> 4 
where t1.Status = 'Active'