TEST MAJ

SELECT meta_value, post_id FROM `wpow_postmeta`, `wpow_posts` WHERE `meta_key` LIKE '_appointment_start' AND ID = post_id AND post_status = 'paid' GROUP BY meta_value

SELECT meta_value, post_id FROM `wpow_postmeta`, `wpow_posts` WHERE `meta_key` LIKE '_appointment_start' AND ID = post_id AND post_status = 'paid' GROUP BY meta_value