MySQL Deltag i samme tabel

For at opnå dette skal du bruge VENSTRE YDRE JOIN operation forener den samme tabel .

SELECT a.*
FROM meta_data a
LEFT OUTER JOIN meta_data b ON a.post_id = b.post_id AND b.meta_value = 'def'
WHERE 
a.meta_value = 'abc'
AND b.post_id IS null