How can I join join more than two SQL table columns in C#

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I have a column named LEADER in 16 tables in my sql database I'd like to join all the tables to show the Leader column and the table it belongs to in datagridview.

What I have tried:

SqlCommand cmd = new SqlCommand("Select GroupLeaders.ID,Account.Leader, Engineers.Leader from GroupLeaders inner join Account on GroupLeaders.id = Account.Leader", conn);

Posted 6-Feb-23 0:00am

Joel Silva 2022

Updated 6-Feb-23 0:36am

Andre Oosthuizen

v2

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Andre Oosthuizen 6-Feb-23 6:18am

Read more on the different jopin statements that you can use to achieve your goal on multiple tables - https://learnsql.com/cookbook/how-to-join-multiple-3-plus-tables-in-one-statement/

Dave Kreskowiak 6-Feb-23 8:42am

Why does it sound like you have 16 tables with essentially the same data in all of them? This sounds like a very badly designed database.

PIEBALDconsult 6-Feb-23 11:12am

Or Billionth Normal Form.

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OriginalGriff · Answer 1 · 2023-02-06T00:36:00

Solution 1

Try something like this:

SQL

SELECT a.LEADER AS [A Leader]
      ,b.LEADER AS [B Leader]
      ,c.LEADER AS [C Leader]
FROM TableA a
JOIN TableB b ON a.ID = b.ID
JOIN TableC c ON a.ID = c.ID

And also read up here: SQL Joins[^]

Posted 6-Feb-23 0:36am

OriginalGriff

Updated 6-Feb-23 0:37am

v2

Comments

Maciej Los 7-Feb-23 11:36am

5ed!