sql唯一和加入

Question

这是一个可爱的一点SQL，我不能写。 :)

我需要做的是这个;

从表（CreatedOn）中为每个用户选择最新值，以获取特定的StatID。然后我需要加入usertable（ssUSER）并选择u.username，我也需要从表中加入detailstatid。即我只需要每个用户的最新结果，然后在用户和detailstatid上进行加入。

SELECT TOP 1000 
    [DetailStatUserLogID] 
    ,[UserID] 
    ,[DetailStatID] 
    ,[OverviewID] 
    ,[Count] 
    ,[StatPercent] 
    ,[SpecificDate] 
    ,[CreatedOn] 
    ,[ModifiedOn] 
    ,[Note] 
    ,[LoggedDate] 
    ,[OverViewGUID] 
FROM [StartStop].[dbo].[DetailStatUserLog] 

SELECT TOP 1000 
    [DetailStatID] 
    ,[DetailStatGUID] 
    ,[NameOfStat] 
    ,[DetailOfStat] 
    ,[CreatedByType] 
    ,[DataType] 
    ,[CreatedByGUID] 
    ,[CreatedBy] 
    ,[ModifiedOn] 
    ,[CreatedOn] 
    ,[OverviewID] 
FROM [StartStop].[dbo].[DetailStat] 

SELECT TOP 1000 
    [UserID] 
    ,[EmailAddress] 
    ,[Authenticated] 
    ,[UserName] 
FROM [StartStop].[dbo].[ssUsers] 

谢谢你也许可以给任何帮助。 :)

Answer 1

尝试：

select /* entered desired fields here */ 
from (select l.*, 
      row_number() over (partition by [UserID], [DetailStatID] 
           order by [CreatedOn] desc) rn 
     from DetailStatUserLog l) ll 
join ssUsers u on ll.[UserId] = u.[UserId] 
Join DetailStat s on ll.[DetailStatId] = s.[DetailStatId] 
where ll.rn=1 

Answer 2

我认为这应该做你想要的。没有你的DDL或数据很难测试。

Select u.UserName, 
     ds.DetailedStat, 
     dsl.CreatedOn, 
     dsl.DetailStatId, 
     dsl.UserId 

From 
(
Select d.UserId, d.DetailStatId, Max(d.CreatedOn) as [CreatedOn] 
From DetailStatUserLog d 
Where d.CreatedOn = (Select Max(CreatedON) 
        From DetailStatUserLog 
        Where UserID = d.UserId 
        And DetailStatId = d.DetailStatId 
        ) 
Group By d.UserId, d.DetailStatId 

)dsl 
Join ssUsers u on dsl.UserId = u.UserId 
Join detailstat ds on dsl.DetailStatId = ds.DetailStatId