Oracle Select Where Value Exists Or Doesn't Exist

I have 3 tables; CASES, USERS and USER_META. For this issue you need to know that the USER_META table has 3 columns; user_id, meta_key and meta_value Each user is associated with m

Solution 1:

I would use a LEFT JOIN

SELECT CASES.*, USERS.*, USER_META.*
FROM CASES
JOIN USERS ON USERS."user_id" = CASES."user_id"
LEFT JOIN USER_META ON USER_META."user_id" = USERS."user_id"AND USER_META."meta_key" = ?

Solution 2:

you need to use OUTER JOIN with the table that may have no results. In Oracle, use (+) near to the field name of the join sentence with this table. This link may help you: http://download.oracle.com/docs/cd/B28359_01/server.111/b28286/queries006.htm