How do I use an IF statement in an MySQL join query?

Question

I have a SQL query that left joins a table in different ways depending on a condition.

SELECT m.id, u.first_name AS otherUser
FROM matches AS m
IF (u.id=m.user2I         


        

Answer 1

You can also have two LEFT JOIN on the same table like this...

LEFT JOIN users AS u ON u.id = m.user1ID
LEFT JOIN users AS u2 ON u2.id = m.user2ID

This is an alternative to using IF statements.