select t.roomtype_name,r.room_id from roomtype t,room r, roomdetail d where t.roomtype_name = '".$roomtype."' and d.check_out < $chkin and r.status = 'ว่าง' and t.roomtype_id=r.roomtype_id and r.room_id = d.room_id
SELECT * FROM ROOM
WHERE ROOM.ROOM_TYPE = :PF_ROOM_TYPE
NOT EXISTS (SELECT 1 FROM ROOMDETAIL
WHERE ROOMDETAIL.ROOM_ID = ROOM.ROOM_ID
AND (ROOMDETAIL.CHECK_IN >=:PF_CHECK_IN
AND ROOMDETAIL.CHECK_OUT =>:PF_CHECK_OUT) )