select user_id, room_id, room_type, days
from (
    select user_id, b.room_id, room_type, 
    datediff(checkout_time, checkin_time) as days
    from guestroom_tb a join checkin_tb b on a.room_id=b.room_id
) temp
where days>1
order by days, room_id, user_id desc