How to select rows that don't have value in a second table

Question

Basically I have a main table (accounts) and a meta table (accounts_meta)... The meta table looks like this:

id | account_id | meta_key | meta_value

What I want to do is only select accounts that do not have 'referrer_paid' as a row in the accounts_meta table...

Here is my code so far...

SELECT a.* FROM accounts AS a
    LEFT JOIN accounts_meta AS am ON a.id = am.account_id AND am.meta_key != 'referrer_paid'
    WHERE a.account_referrer != ''
    GROUP BY a.id

Hopefully I am making sense. What am I doing wrong?

Answer 1

tiny change from @lexu:

SELECT * 
  FROM accounts 
 WHERE id NOT IN ( select account_id 
                     from `account_meta_table` 
                    where meta_key = 'referrer_paid'
                  );

Answer 2

SELECT * 
  FROM accounts 
 WHERE id NOT IN ( select DISTINCT account_id 
                     from `account_meta_table` 
                    where meta_key != 'referrer_paid'
                  );