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我有一个具有以下定义的表：

CREATE TABLE [dbo].[Due] (
[dueID]           INT            IDENTITY (1, 1) NOT NULL,
[dueTypeID]       INT            NOT NULL,
[vehicleID]        INT            NOT NULL,
[dueDate]         DATE           NULL,
...

在这里，我想生成一个查询，其输出为

VehicleID  Type1.dueDate  Type2.dueDate  Type3.dueDate ...

（到期日应该是该到期类型的车辆的最高到期日）

我编写了以下查询来执行此操作：

select vehicleNumber, A.dueDate, B.dueDate, C.dueDate, D.dueDate, E.dueDate, F.dueDate 
FROM Vehicle INNER JOIN 
(SELECT Max(dueDate) as dueDate,vehicleID from Due where dueTypeID = '1' GROUP BY Due.vehicleID) As A ON Vehicle.vehicleID = A.vehicleID INNER JOIN
(SELECT Max(dueDate) as dueDate,vehicleID from Due where dueTypeID = '2' GROUP BY Due.vehicleID) As B ON Vehicle.vehicleID = A.vehicleID INNER JOIN
(SELECT Max(dueDate) as dueDate,vehicleID from Due where dueTypeID = '3' GROUP BY Due.vehicleID) As C ON Vehicle.vehicleID = A.vehicleID INNER JOIN
(SELECT Max(dueDate) as dueDate,vehicleID from Due where dueTypeID = '4' GROUP BY Due.vehicleID) As D ON Vehicle.vehicleID = A.vehicleID INNER JOIN
(SELECT Max(dueDate) as dueDate,vehicleID from Due where dueTypeID = '5' GROUP BY Due.vehicleID) As E ON Vehicle.vehicleID = A.vehicleID INNER JOIN
(SELECT Max(dueDate) as dueDate,vehicleID from Due where dueTypeID = '6' GROUP BY Due.vehicleID) As F ON Vehicle.vehicleID = A.vehicleID

问题是，对于特定类型没有到期日的车辆正在获取其他车辆的价值。请帮助我弄清楚如何解决这个问题，如果我以正确的方式这样做，或者是否有更好的方法来做到这一点？

（抱歉，如果我尝试查找问题但找不到正确的关键字来搜索问题，则该问题是重复的）

非常感谢你帮助我。

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1 回答 1

1

尝试这个：

 select vehicleNumber, 
     Max(case When dueTypeID = '1' Then dueDate Else null end) Typ1dueDate, 
     Max(case When dueTypeID = '2' Then dueDate Else null end) Typ2dueDate, 
     Max(case When dueTypeID = '3' Then dueDate Else null end) Typ3dueDate, 
     Max(case When dueTypeID = '4' Then dueDate Else null end) Typ4dueDate, 
     Max(case When dueTypeID = '5' Then dueDate Else null end) Typ5dueDate, 
     Max(case When dueTypeID = '6' Then dueDate Else null end) Typ6dueDate
 FROM Due d join Vehicle v 
     On v.vehicleId = d.vehicleId 
 Group By v.vehicleNumber
于 2013-05-27T18:28:36.710 回答