Question

我的问题是：

有一个sql存储过程，它为我提供了一个给定hotelid和bookin，bookout日期的hotel_reservation表中两个日期之间的免费房间列表。

以下是程序：

    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

Room表的定义：

room_id          int
hotel_id         int
room_type_id     varchar
price            money
room_description varchar

在房间表中，我使用了room_id和Hotel_id的重复密钥，因为ID为201的酒店可以有room_id 101也可以{id} 202的酒店{101}避免从重复的列我用过它。

room_id

的定义

hotel_reservation table

问题是：

当我运行此程序时如果用户在201酒店预订了房间号为101的房间，则另一位用户无法在酒店看到ID为202的房间，其房间为202.它会从酒店预订所有101个房间。

如何改进我的程序来克服这个问题？

感谢您的观看..

Image1，Image2

Answer 1

更改为允许多个条件的NOT EXSTS？

在这种情况下，它可以检查两个酒店和房间ID。

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

编辑：

感谢Andriy M用一些括号

来纠正我的AND / OR运算符优先级

Answer 2

这是一个可能的解决方案的快速运行。（抱歉，我没时间测试它......）

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

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

RETURN

在sql中使用“Not In”语句获取重复的键

2 个答案: