Question

I’m working with three tables, and for simplicity’s sake let’s call them table A, B, and C. Both tables A and B have a column called id, as well as one other column, Aattribute and Battribute, respectively. Column c also has an id column, and two other columns which hold values for A.id and B.id. Now, in my code, I have easy access to values for both Aattribute and Battribute, and want to delete the row at C, so effectively I want to do something like this:

DELETE FROM C WHERE aid=(SELECT id FROM A WHERE Aattribute='myvalue') AND bid=(SELECT id FROM B WHERE Battribute='myothervalue')

But this obviously doesn’t work. Is there any way to make a single complex query, or do I have to run three queries, where I first get the value of A.id using a SELECT with ‘myvalue’, then the same for B.id, then use those in the final query?
[Edit: it’s not letting me comment, so in response to the first comment on this: I tried the above query and it did not work, I figured it just wasn’t syntactically correct. Using MS Access, for what it’s worth. ]

Answer 1

You must use IN instead of =.

DELETE
FROM   C
WHERE  aid IN
       (SELECT id
       FROM    A
       WHERE   Aattribute='myvalue'
       )
AND    bid IN
       (SELECT id
       FROM    B
       WHERE   Battribute='myothervalue'
       )