結合兩個SQL查詢PDO

Question

我很困擾以下問題。我有一系列的表格：

我想要做的是獲得一個房間的所有信息，假設預訂量不超過該房間的可用房間數量。

因此，要獲得我的房間詳情我的SQL是這樣的：

SELECT Rooms.RoomID as RoomID, 
     RoomName, NumOfRooms, 
     MaxPeopleExistingBeds, 
     MaxExtraBeds, 
     MaxExtraPeople, 
     CostPerExtraPerson, 
     MaximumFreeChildren, 
     IncludeBreakfast, 
     MinRate 
    FROM Rooms, RoomDetails 
    WHERE Rooms.AccommodationID = :aid AND 
     Rooms.RoomID = RoomDetails.RoomID 
GROUP BY RoomName 

，其在回讓我的那些房間詳細信息列表如下：

然後我用這個查詢得到預訂的數量，並且在房間的ID：

SELECT Booking.RoomID, 
     count(Booking.RoomID) as Bookings 
    FROM Booking 
    WHERE ArriveDate >= :aDate AND 
     DepartDate <= :dDate AND 
     AccommodationID = :aid 
GROUP BY RoomID 

我再結合兩者，並使用THI兩個陣列反饋在一個陣列中S功能：

public function get_availability($aid, $aDate, $dDate) { 
     $stmt = $this->db->prepare('SELECT Rooms.RoomID as RoomID, RoomName, NumOfRooms, MaxPeopleExistingBeds, MaxExtraBeds, MaxExtraPeople, CostPerExtraPerson, MaximumFreeChildren, IncludeBreakfast, MinRate FROM Rooms, RoomDetails WHERE Rooms.AccommodationID = :aid AND Rooms.RoomID = RoomDetails.RoomID GROUP BY RoomName'); 
     $stmt->bindValue(':aid', $aid); 
     $stmt->execute(); 
     $rooms = $stmt->fetchAll(PDO::FETCH_ASSOC); 
     $stmt2 = $this->db->prepare('SELECT Booking.RoomID, count(Booking.RoomID) as Bookings FROM Booking WHERE ArriveDate >= :aDate AND DepartDate <= :dDate AND AccommodationID = :aid GROUP BY RoomID'); 
     $stmt2->bindValue(':aid', $aid); 
     $stmt2->bindValue(':aDate', $aDate); 
     $stmt2->bindValue(':dDate', $dDate); 
     $stmt2->execute(); 
     $bookings = $stmt2->fetchAll(PDO::FETCH_ASSOC); 
     $room = array($rooms, $bookings); 

     return (!empty($room)) ? $room : false; 
    } 

的事情是，我真正想要做的是隻返回了房間的詳細信息，其中NumOfRooms小於預訂數。

因此，例如，如果我預訂了$預訂，如果它告訴我對於ID號爲4的房間，我有3次預訂，而我的NumOfRooms爲1，那麼我知道我沒有這周的容量任何更多的預訂。但是，如果我有一個預訂和一個容量，那麼它仍然是滿的。但是，如果我的NumOfRoom爲2，並且預訂達到1，我知道我有空間。

所以基本上如果NumOfRooms> BookingCount那麼空間可用。

我怎麼能合併查詢和簡化我的代碼，以使這一切成爲可能？

IE把它簡單地說，我如何從BookingDetails中選擇所有的信息，並給出一個DepartDate和RoomID，其中NumOfRooms> count（Booking.RoomID）（它在這些日期和房間號等於房間的房間號）。

Answer 1

您的問題可以通過簡單地更新SQL語句本身來解決：

SELECT r.RoomID AS RoomID, 
     RoomName, 
     NumOfRooms, 
     MaxPeopleExistingBeds, 
     MaxExtraBeds, 
     MaxExtraPeople, 
     CostPerExtraPerson, 
     MaximumFreeChildren, 
     IncludeBreakfast, 
     MinRate 
FROM Rooms r 
JOIN RoomDetails rd 
    ON r.RoomID = rd.RoomID 
JOIN (
    SELECT b.RoomID, 
      AccommodationID, 
      count(b.RoomID) AS Bookings 
    FROM Booking b 
    WHERE ArriveDate >= :aDate 
     AND DepartDate <= :dDate 
    GROUP BY RoomID 
) t 
    ON t.AccommodationID = r.AccommodationID 
WHERE r.AccommodationID = :aid 
    AND t.Bookings < NumOfRooms 
GROUP BY RoomName 

Answer 2

您可以選擇的所有每間客房的預訂數爲所需日期範圍內的子查詢，然後LEFT JOIN針對子查詢根據您所需的AccommodationID和期望的NumOfRooms > BookingCount條件篩選出的房間列表。此處的關鍵在於用於此子查詢的聯接類型，因爲內部聯接會將結果限制爲僅實際預訂了房間。

SELECT Rooms.RoomID as RoomID, 
      RoomName, NumOfRooms, 
      MaxPeopleExistingBeds, 
      MaxExtraBeds, 
      MaxExtraPeople, 
      CostPerExtraPerson, 
      MaximumFreeChildren, 
      IncludeBreakfast, 
      MinRate, 
      BookingCount 
     FROM Rooms 
INNER JOIN RoomDetails on Rooms.RoomID = RoomDetails.RoomID 
LEFT JOIN (
       SELECT Booking.RoomID, 
         count(Booking.RoomID) as BookingCount 
       FROM Booking 
       WHERE ArriveDate >= :aDate AND 
         DepartDate <= :dDate 
      GROUP BY Booking.RoomID 
      ) RoomBookings ON Rooms.RoomID = RoomBookings.RoomID 
    WHERE Rooms.AccommodationID = :aid 
     AND NumOfRooms > BookingCount 
    GROUP BY RoomName