Question

I have this query:

SELECT Auctions.ID 
FROM Auctions
INNER JOIN Products ON Auctions.ProductID = Products.ID

Now as far as i know if i have an auction:

ID | ProductID
1  |   12

And the ProductID 12 is not on the Products table, so the row wont be selected.

If i am right, i want to delete all the rows that didn’t found the Product ID on the Products table. (the products that couldn’t find a JOIN)

How can i do that?

Answer 1

DELETE Auctions WHERE ProductId NOT IN(SELECT ProductId FROM Products)

Of course, after you do this, do yourself a favor and create a Relationship from Auctions.ProductId to Products.ProductId if you don’t want to do this again.