select a.user_id,a.room_id,b.room_type,a.days
from 
(select room_id,user_id,datediff(checkout_time,checkin_time) as days
from checkin_tb
where datediff(checkout_time,checkin_time) >=2) a
left join guestroom_tb b
on a.room_id=b.room_id
order by days,room_id,user_id desc;