TSQL关于连接表和n-m关系的东西 [英] TSQL something about join table and n - m relations
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问题描述
今天我被卡住了
我有三张桌子,逻辑上这是zwei桌子名称和房间的关系。
-Name(n)
-A加入表
-Room(n)
现在我想让所有名字 - 行独特,其中洁具工作在房间x,y和z
请帮助我,今天我是一个伟大的理想选择;)
Today I am "to be stuck"
I have three Tables, logical this are zwei tables Name and Room with a n to m relation.
-Name (n)
-A join table
-Room (n)
Now i want to get all Names-Rows unique, where ware "working" in room x,y and z
Please help me, today am am a big ideot ;)
User
UserID Name Adress bla...
a Max
b Peter
c Ben
Join_User_Room
JoinID UserID RoomID
d a x
e a y
f a z
g b x
h b y
i b z
Room
RoomID Name
x Room1
y Room2
z Room3
我是什么尝试过:
What I have tried:
Left join and right joins and other crazy sql stuff
推荐答案
试试这个:
Try this:
SELECT u.* FROM [User] u
JOIN (SELECT ju.UserID FROM Join_User_Room ju GROUP BY ju.UserID) jg ON jg.UserID = u.UserID
当您发布代码片段(例如您的SQL)时,请尽量确保它们正常工作:这不会出于多种原因!
And when you post code fragments (such as your SQL) please try to ensure they work: that won't for loads of reasons!
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