Given a table customer holding customers information and the referee.
+------+------+-----------+ | id | name | referee_id| +------+------+-----------+ | 1 | Will | NULL | | 2 | Jane | NULL | | 3 | Alex | 2 | | 4 | Bill | NULL | | 5 | Zack | 1 | | 6 | Mark | 2 | +------+------+-----------+
Write a query to return the list of customers NOT referred by the person with id '2'.
For the sample data above, the result is:
+------+ | name | +------+ | Will | | Jane | | Bill | | Zack | +------+