Question

I am looking to dynamically select specific columns within a join query in which a specific field will only be selected if the value of another is not equal to 0.

So here’s what I have going on.

The query uses the following 3 tables, users – schools – campuses

I would like to select all of the data from users, and if the campus_id field of users is not equal to 0, then I would like to include the campus name field of campuses where campuses.id = users.campus_id, how would I do this?

Answer 1

You could use CASE WHEN

SELECT column1, column2, (CASE WHEN U.campus_id<>0 THEN campus_name) FROM USERS U, CAMPUSES C
WHERE (U.campus_id <>0 AND C.id=U.campus_id)