Question

选择其车辆从未分配给任何客户的所有经销商的列表，即PS3_VehicleBooking中没有该车辆，且承诺日期大于今天的日期。

要使用的3个表是 -

CREATE TABLE PS3_Dealer(
    ID int IDENTITY(1,1) NOT NULL Primary KEY,
    DealerID varchar(255) NULL,
    DealerName varchar(255) NOT NULL,
    ContactNo varchar(255) NOT NULL,
    NoOfVehicles bigint NOT NULL,
    CommittedDate date NOT NULL
);

create table PS3_Vehicle 
  (
    ID int IDENTITY(1,1) NOT NULL Primary Key,
    DealerID varchar(255) NOT NULL,
    VehicleID varchar(255) UNIQUE NOT NULL,
    VehicleName varchar(255) NOT NULL,
    Capacity BIGINT NOT NULL

  );

  create table PS3_VehicleBooking
  (
  ID int IDENTITY(1,1) NOT NULL Primary Key,
  BookingID varchar(255) NOT NULL UNIQUE,
  VehicleID varchar(255) NOT NULL,
  StartDate date NOT NULL,
  EndDate date NOT NULL
  );

PS3_Dealer值 -

DealerID DealerName ContactNo NoOfVehicles CommittedDate
1        ng         9         5             2013-12-12
2        nikki      5         7             2013-12-25
3        nik        4         6             2013-10-11
4        hj         2         2             2014-11-10
5        pk         67        8             2013-10-10

PS3_Vehicle

DealerID VehicleID VehicleName Capacity
1        V1        ind         4
2        V2        innova      5
3        V3        innova      6
1        V4        ula         8
4        V5        hkk         2
5        V6        ghi         9
2        V7        bjhgi       4

PS3_VehicleBooking -

BookingID VehicleID StartDate     EndDate
  1         V1      2013-12-13     2013-12-17 
  2         V2      2013-10-11     2013-10-13
  3         V3      2014-12-10     2014-12-13
  4         V4      2012-10-10     2012-10-13
  5         V2      2013-12-14     2013-12-18

预期结果 -

DealerID  DealerName ContactNo NoOfVehicles CommittedDate

4          hj        2          2           2014-11-10

但我得到了 -

DealerID  DealerName ContactNo NoOfVehicles CommittedDate

4          hj        2          2           2014-11-10
2          Nikki     5          7           2013-12-25

我不想要经销商ID 2，因为经销商ID 2提供的V2出现在PS3中。

我的查询是 -

SELECT h.DealerID,
       h.DealerName,
       h.ContactNo,
       h.NoOfVehicles,
       h.CommittedDate
FROM   PS3_Dealer h
       INNER JOIN(SELECT DealerID,
                         PS3_VehicleBooking.VehicleID
                  FROM   PS3_Vehicle
                         LEFT JOIN PS3_VehicleBooking
                           ON PS3_Vehicle.VehicleID = PS3_VehicleBooking.VehicleID) w
         ON h.DealerID = w.DealerID
WHERE  w.VehicleID IS NULL
       AND h.CommittedDate > GETDATE()

请纠正我错在哪里？

Answer 1

编辑实际回答问题

你得到的是Nikki，因为她的车（V7）确实不在预订表中。这应该排除Nikki。

SELECT h.DealerID,
   h.DealerName,
   h.ContactNo,
   h.NoOfVehicles,
   h.CommittedDate
FROM PS3_Dealer d
WHERE NOT EXISTS 
 (SELECT *
  FROM PS3_VehicleBookingb
  JOIN PS3_Vehiclev ON b.vehicleID = v.VehicleID
  JOIN PS3_Dealerd2 ON d2.dealerID = v.dealerID
  WHERE d2.dealerID = d.dealerID)
AND CommittedDate > Current_date()

http://sqlfiddle.com/#!2/fb365/19

Answer 2

问题在于DealerID 2有2辆车。一个有预订，另一个没有。当你运行

SELECT DealerID,
        PS3_VehicleBooking.VehicleID
FROM   PS3_Vehicle
        LEFT JOIN PS3_VehicleBooking
        ON PS3_Vehicle.VehicleID = PS3_VehicleBooking.VehicleID

您将获得一条DealerID 2的记录，其中包含NULL VehicleID，另一条记录为无NULL车辆ID。

您可以尝试运行下面的语句以获得所需的结果（可能不是最佳的，但它是对您的陈述的修复）：

SELECT h.DealerID,
       h.DealerName,
       h.ContactNo,
       h.NoOfVehicles,
       h.CommittedDate
FROM   PS3_Dealer h
       INNER JOIN(SELECT DealerID,
                         MAX(PS3_VehicleBooking.VehicleID) as VehicleID
                  FROM   PS3_Vehicle
                         LEFT JOIN PS3_VehicleBooking
                           ON PS3_Vehicle.VehicleID = PS3_VehicleBooking.VehicleID
                    GROUP BY DealerID
                    ) w
         ON h.DealerID = w.DealerID
WHERE  w.VehicleID IS NULL
       AND h.CommittedDate > GETDATE()

SQL Server连接查询未检索到正确的结果

2 个答案: