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raouafi avatar image
raouafi asked

SQL Join

Hello, I have two tables A(id,user_id,info,...) and B(B_id,A_id), I'm unable to write the SQL request that gives me all fields of a given user from the table A with B_id if it exist. Could any one help me please ?
join
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Wilfred van Dijk avatar image
Wilfred van Dijk answered
If you use this code : select A.*, B.* from table_a as A join table_b as B on A.id = B.A_id only the matching ones are showed. If you change "join" to "left join", everything from table_a is shown and fields from table_b are NULL if there's no match. see [this article][1] [1]: https://www.mssqltips.com/sqlservertip/1667/sql-server-join-example/
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Tom Staab avatar image Tom Staab ♦ commented ·
If I understand the requirements correctly, I believe the columns should be A.*, B.B_id.
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Wilfred van Dijk avatar image Wilfred van Dijk commented ·
code clarified
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raouafi avatar image raouafi commented ·
It works when modified this way : SELECT A.* , B.* FROM table_a AS A LEFT JOIN table_b AS B ON A.id = B.A_id WHERE A.userId = MyUser; Thanks a lot.
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