CODEWITHSUNDEEP
mysqlsqlsql-server
Ctrl_Alt_Defeat
Ctrl_Alt_Defeat

Reputation: 4009

Correct Join Query for SQL Query

I currently have the following Query

SELECT * FROM tbl_Cars c
        INNER JOIN tbl_Car_Parts cp ON c.Id = cp.Id
        INNER JOIN tbl_Car_Factory cf ON cp.Id = cf.Id

However I have now realised that there are some Ids which are in the Cars Table which are then not in the Car Parts table so these are being omitted from my results while I want them included. I tried changing my INNER JOIN to a LEFT OUTER JOIN but it made no difference in the result set I am returned?

Upvotes: 3

Views: 92

Answers (2)

Rafa Paez
Rafa Paez

Reputation: 4860

Use LEFT OUTER JOIN in both of the joins. 

SELECT * FROM tbl_Cars c
    LEFT OUTER JOIN tbl_Car_Parts cp ON c.Id = cp.Id
    LEFT OUTER JOIN tbl_Car_Factory cf ON cp.Id = cf.Id

Otherwise the second INNER JOIN will invalidate your first LEFT OUTER JOIN for those records that does not have ID (does not join) in the tbl_Car_Parts table.

After a LEFT OUTER JOIN you may be only use again INNER JOIN if the table you are joining is not related with the previous ones that are joined using the LEFT OUTER JOIN.

Upvotes: 3

SoulTrain
SoulTrain

Reputation: 1904

LEFT JOIN should have definitely solved your problem, Not sure why it didnt work. Just to be safe I used Left join on both the tables...

SELECT * FROM tbl_Cars c
        LEFT JOIN tbl_Car_Parts cp ON c.Id = cp.Id
        LEFT JOIN tbl_Car_Factory cf ON cp.Id = cf.Id

Upvotes: 0

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