Question

I’ve come across some SQL queries in Oracle that contain ‘(+)’ and I have no idea what that means. Can someone explain its purpose or provide some examples of its use? Thanks

Answer 1

It’s Oracle’s synonym for OUTER JOIN.

SELECT * FROM a, b WHERE b.id(+) = a.id 

gives same result as

SELECT * FROM a      LEFT OUTER JOIN b      ON b.id = a.id