SELECT * FROM table a,table b WHERE a.id = b.id AND a.id IS NOT NULL A
+ND a.id != '';
and
SELECT * FROM table a,table b WHERE a.first_name = b.first_name AND a.
+last_name = b.last_name
AND (a.id IS NULL or a.id = '') AND (b.id IS NULL or b.id = '');
[download]