Question

My question is:

Have an sql stored procedure which brings me a list of free rooms between two date in an hotel_reservation table for a given hotelid and bookin ,bookout dates.

Here is the procedure :

    ALTER PROCEDURE dbo.StoredProcedure1
    (
    @DateStart date,
    @DateEnd date,
    @hotel_id int
    )

AS
    SELECT DISTINCT room_type_id, room_id
    FROM Room
WHERE room_id NOT IN (
        SELECT room_id
        FROM Hotel_Reservation
        WHERE @DateStart BETWEEN bookingStart AND bookingEnd
    OR @DateEnd BETWEEN bookingStart AND bookingEnd
    or bookingStart BETWEEN @DateStart AND @DateEnd  
    or bookingEnd BETWEEN @DateStart AND @DateEnd
    and hotel_id = @hotel_id 
) and hotel_id = @hotel_id 
    RETURN

Definition of Room table :

room_id          int
hotel_id         int
room_type_id     varchar
price            money
room_description varchar

In room table I used duplicated key with room_id and Hotel_id cause Hotel with id 201 can have room_id 101 also Hotel with id 202 can have room_id 101 to avoid from repeated columns I used this.

definition of hotel_reservation table

reservation_id int
customer_id    varchar
bookingStart   date
bookingEnd     date
status         varchar
room_id        int
hotel_id       int
date           date

The Problem is:

When I run this procedure If a user booked a room with id 101 at hotel 201, another user cant see the room with id 101 at hotel with id 202. It books all the 101 id rooms from the hotels.

How can I improve my procedure to overcome this problem?

Thanks for viewing..

Image1, Image2

Answer 1

Change to NOT EXSTS which allows multiple conditions?

In this case it can check both hotel and room ids.

SELECT DISTINCT room_type_id, room_id
FROM Room R
WHERE NOT EXISTS (
        SELECT *
        FROM Hotel_Reservation H
        WHERE
    (
    @DateStart BETWEEN H.bookingStart AND H.bookingEnd
    OR @DateEnd BETWEEN H.bookingStart AND H.bookingEnd
    or H.bookingStart BETWEEN @DateStart AND @DateEnd  
    or H.bookingEnd BETWEEN @DateStart AND @DateEnd
    )
    and  --here is where we check **that room for that hotel**
    H.hotel_id = R.hotel_id and H.room_id = R.room_id
) 
and 
R.hotel_id = @hotel_id

Edit:

Thank you to Andriy M for correcting my AND/OR operator precedence with some brackets