[英]SQL Join to only one record in one to many relationship
I have the following query: 我有以下查询:
SELECT c.[ClientID]
,u.[AccessId]
FROM [tblClient] c
INNER JOIN [tblUser] u ON u.[Id] = c.[UserId]
This tblUser has multiple ID's for each UserID row. 此tblUser的每个UserID行都有多个ID。
So it would look like this: 所以它看起来像这样:
UserID AccessID
1 AD2F0A-965B78414-2B34906F2-0127AA5A
1 ID2F0A9-65B784-142B34906-F20127AA5A
1 UD2F0A9-65B78-4142B34906F-20127AA5A
2 TD2F0A9-65B784142-B34906F-20127AA5A
2 RD2F0A9-65B784142B3-4906-F20127AA5A
3 WD2F0A96-5B784142-B34906F201-27AA5A
3 ZD2F0A96-5B784-142B34-906F2-0127AA5A
3 CD2F0A965-B784142B3-4906F20-127AA5A
Is there a way to only get the top(or 1) AccessId for each UserID? 有没有一种方法只能获取每个UserID的最高(或1)AccessId? It doesnt matter which AccessID i get, I just want 1 of them.
我得到哪个AccessID都没有关系,我只想要其中一个。
Thanks 谢谢
SELECT c.[ClientID], MAX(u.[AccessId])
FROM [tblClient] c
INNER JOIN [tblUser] u
ON u.[Id] = c.[UserId]
GROUP BY c.[ClientID]
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