Question

我在编写sql时遇到了从表中获取可用空间的问题。

我的表格结构如下。

Table Booking
ID | START_DATE | END_DATE


Table BookingRoom (Intermediate Table)
ID   | BOOKING_ID   |ROOM_ID

房间可以链接到许多预订，预订可以包含许多房间

Table Room
Contains the ID room

我已经尝试了但是如果一个房间在不同的日期与2个不同的预订相关联，则会出现问题，比较将仅与第一个预订ID相关

SELECT DISTINCT r.ID FROM room AS r ,booking AS b,bookingroom AS br
 WHERE r.ID = br.ID_ROOM
 AND b.ID = br.ID_BOOKING
 AND (
           b.END_DATE < '05/14/2013'
        OR b.START_DATE > '05/15/2013'
     )

有人可以帮我编写SQL以获取签入和结帐日期之间的可用空间。

Answer 1

如果您想要的是所有可用日期范围内的房间列表，那么以下内容可能会有效：

Select Room.Id
From Room
Where Room.Id Not In    (
                        Select RoomId
                        From BookingRoom
                            Join Booking
                                On Booking.Id = BookingRoom.BookingId
                        Where Booking.StartDate <= 'DesiredEndDate'
                            And Booking.EndDate >= 'DesiredStartDate'
                        )
Order By Room.Id

因此，使用原始示例，我们可能会得到：

Select Room.Id
From Room
Where Room.Id Not In    (
                        Select RoomId
                        From BookingRoom
                            Join Booking
                                On Booking.Id = BookingRoom.BookingId
                        Where Booking.StartDate <= '2013-05-15'
                            And Booking.EndDate >= '2013-05-14'
                        )
Order By Room.Id

Answer 2

您需要为“在第X天进行的所有预订”定义清晰的记录集，然后使用外部联接来检索那些没有预订当天的房间。

SET @myDate = #someDay#
SELECT R.ID
FROM Room R
WHERE R.ID NOT IN (
    SELECT BR.ROOM_ID
    FROM BookingRoom BR
    INNER JOIN Booking B ON BR.Booking_ID = B.ID
    WHERE @myDate BETWEEN B.start_date and B.end_date
)

修改

由于您在预订期间需要所有开放空间，因此您需要执行更复杂的查询。我假设您已经在外面加载了有问题的日期，因为基于日期的多对多查询是PITA。

SET @dateStart = #Start# SET @dateEnd = #End# SELECT R.ID FROM Room R WHERE R.ID NOT IN ( SELECT BR.ROOM_ID FROM BookingRoom BR INNER JOIN Booking B ON BR.Booking_ID = B.ID WHERE B.start_date BETWEEN @dateStart AND @dateEnd AND B.end_date BETWEEN @dateStart AND @dateEnd )

房间预订查询

2 个答案: