Question

Scenario:

Let’s say I have two tables, TableA and TableB. TableB’s primary key is a single column (BId), and is a foreign key column in TableA.

In my situation, I want to remove all rows in TableA that are linked with specific rows in TableB: Can I do that through joins? Delete all rows that are pulled in from the joins?

DELETE FROM TableA  FROM    TableA a    INNER JOIN TableB b       ON b.BId = a.BId       AND [my filter condition] 

Or am I forced to do this:

DELETE FROM TableA WHERE    BId IN (SELECT BId FROM TableB WHERE [my filter condition]) 

The reason I ask is it seems to me that the first option would be much more effecient when dealing with larger tables.

Thanks!

Answer 1

DELETE TableA FROM   TableA a        INNER JOIN TableB b                ON b.Bid = a.Bid                   AND [my filter condition]  

should work