Hãy thử cái này:
SELECT *
FROM `timeslots`
LEFT JOIN schedule ON timeslots.timeslot_id = schedule.schedule_timeslot
WHERE schedule.schedule_id IS NULL or schedule.schedule_date <> '2011-08-01'
LIMIT 0, 30
Hãy thử cái này:
SELECT *
FROM `timeslots`
LEFT JOIN schedule ON timeslots.timeslot_id = schedule.schedule_timeslot
WHERE schedule.schedule_id IS NULL or schedule.schedule_date <> '2011-08-01'
LIMIT 0, 30