@strangisgroup Let us assume there are 5 rooms of General Category in a hotel. Mario Brown books a room from 07-06-2018 to 09-06-2018 then for Mario Brown (the customer) check-in date will be 07-06-2018 and the check-out date will be 09-06-2018. And the check-out date of one customer can be the check-in date of another customer. Hence, on 09-06-2018 another customer can check-in in this room.
So if Henry (another customer) books a room for 08-06-2018 to 10-06-2018 then the number of rooms available for him will be 4 rooms, and if he makes a booking for 09-06-2018 to 10-06-2018 then the number of rooms available for him will be 5 rooms.
If all the 5 rooms are booked in that date range then it will not show that room type.