Question

我的问题是：我如何通过PositionAssetId排序子查询，然后根据表TrxAssetPool跟随其相关的PhysicalAssetId？

我需要LEFT JOIN，因为并非所有的Position和Physical都链接在一起。一些职位/实际职位是独立的。物理可能存在于PhysicalAsset和TrxPhysicalAsset中，但由于未链接到任何位置而在TrxAssetPool中不存在。反之亦然。这些数据也需要显示。

CREATE TABLE `PositionAssets` (
  `Id` int(5) unsigned NOT NULL,
  `Code` varchar(50) NOT NULL,
  `Desc` varchar(200) NOT NULL,
  PRIMARY KEY (`Id`)
);
CREATE TABLE `PhysicalAssets` (
  `Id` int(5) unsigned NOT NULL,
  `Code` varchar(50) NOT NULL,
  `Desc` varchar(200) NOT NULL,
  PRIMARY KEY (`Id`)
);
CREATE TABLE `TrxPositionAssets` (
  `Id` int(5) unsigned NOT NULL,
  `MaintTrxId` int(5) unsigned NOT NULL,
  `PositionAssetId` int(5) NOT NULL,
  PRIMARY KEY (`Id`,`MaintTrxId`)
);
CREATE TABLE `TrxPhysicalAssets` (
  `Id` int(5) unsigned NOT NULL,
  `MaintTrxId` int(5) unsigned NOT NULL,
  `PhysicalAssetId` int(5) NOT NULL,
  PRIMARY KEY (`Id`,`MaintTrxId`)
);
CREATE TABLE `TrxAssetPool` (
  `Id` int(5) unsigned NOT NULL,
  `MaintTrxId` int(5) NOT NULL,
  `PositionAssetId` int(5) NOT NULL,
  `PhysicalAssetId` int(5) NOT NULL,
  PRIMARY KEY (`Id`)
);
INSERT INTO `PositionAssets` (`Id`, `Code`, `Desc`) VALUES
  ('1', 'PositionC', 'Air conditioner'),
  ('2', 'PositionB', 'Laptop'),
  ('3', 'PositionA', 'Mobile Phone')
  ;
INSERT INTO `PhysicalAssets` (`Id`, `Code`, `Desc`) VALUES
  ('1', 'PhysicalD', 'Dunlop Car Tyre'),
  ('2', 'PhysicalA1', 'Samsung'),
  ('3', 'PhysicalB2', 'Acer'),
  ('4', 'PhysicalB1', 'Lenovo')
  ;
INSERT INTO `TrxPositionAssets` (`Id`, `MaintTrxId`, `PositionAssetId`) VALUES
  ('1', '1', '2'),
  ('2', '1', '3'),
  ('3', '1', '1')
  ;
INSERT INTO `TrxPhysicalAssets` (`Id`, `MaintTrxId`, `PhysicalAssetId`) VALUES
  ('1', '1', '2'),
  ('2', '1', '3'),
  ('3', '1', '1'),
  ('4', '1', '4')
  ;
INSERT INTO `TrxAssetPool` (`Id`,`MaintTrxId`,`PositionAssetId`,`PhysicalAssetId`) VALUES
  ('1', '1', '3', '2'),
  ('2', '1', '2', '4'),
  ('3', '1', '2', '3')
  ; 

SELECT DataType, DataCode, DataDesc 
FROM ( 
    SELECT 'Position' AS DataType, pos.Code AS DataCode, pos.Desc AS DataDesc
        FROM TrxPositionAssets trxpos
        JOIN PositionAssets pos ON pos.Id = trxpos.PositionAssetId
        LEFT JOIN TrxAssetPool trxpool ON (trxpool.PositionAssetId = trxpos.PositionAssetId and trxpool.MaintTrxId = trxpos.MaintTrxId)
        WHERE trxpos.MaintTrxId = 1
    UNION
    SELECT 'Physical' AS DataType, phy.Code AS DataCode, phy.Desc  AS DataDesc
        FROM TrxPhysicalAssets trxphy
        JOIN PhysicalAssets phy ON phy.Id = trxphy.PhysicalAssetId
        LEFT JOIN TrxAssetPool trxpool ON (trxpool.PhysicalAssetId = trxphy.PhysicalAssetId and trxpool.MaintTrxId = trxphy.MaintTrxId)
        WHERE trxphy.MaintTrxId = 1  
) DataPool

Sample at sqlfiddle.com

当前结果：

DataType    DataCode    DataDesc

Position    PositionA   Mobile Phone
Position    PositionB   Laptop
Position    PositionC   Air conditioner
Physical    PhysicalA1  Samsung
Physical    PhysicalB1  Lenovo
Physical    PhysicalB2  Acer
Physical    PhysicalD   Dunlop Car Tyre

预期结果：

DataType    DataCode    DataDesc

Position    PositionA   Mobile Phone
Physical    PhysicalA1  Samsung
Position    PositionB   Laptop
Physical    PhysicalB1  Lenovo
Physical    PhysicalB2  Acer
Position    PositionC   Air conditioner
Physical    PhysicalD   Dunlop Car Tyre

空调与任何物理无关。 Dunlop汽车轮胎与任何职位都没有关系。

Answer 1

在查询末尾，

ORDER BY DATA.DataId ASC;

Answer 2

您需要在子查询中选择所需的信息。另外，LEFT JOIN不是必需的，因为WHERE撤消了它们，并且您可能想要UNION ALL：

SELECT Data.[DataId], Data.[TrxnDataId], Data.[Type]
FROM ((SELECT pa.[Id] AS DataId, tpa.[Id] AS TrxnDataId, 'Position' AS Type,
              tap.PositionAssetId, 1 as ord
       FROM {TrxPositionAssets} tpa JOIN
            {PositionAssets} pa
            ON pa.[Id] = tpa.[PositionAssetId] JOIN
            TrxAssetPool} tap
            ON tap.[PositionAssetId] = pa.[Id] AND tap.[TrxId] = tpa.[TrxId])
         WHERE tpa.[TrxId] = @TrxId 
      ) UNION ALL
      (SELECT pa.[Id] AS DataId, tpa.[Id] AS TrxnDataId, 'Physical' AS Type,
              tap.PositionAssetId, 2 as ord
       FROM {TrxPhysicalAssets} tpa JOIN
            {PhysicalAssets} pa
            ON pa.[Id] = tpa.[PhysicalAssetId] JOIN
            {TrxAssetPool} tap
            ON tap.[PhysicalAssetId] = pa.[Id] AND tap.[TrxId] = tpa.[TrxId]
       WHERE tpa.[TrxId] = @TrxId
      )
     ) data 
ORDER BY PositionAssetId, ord, dataId;

Answer 3

要解决您的问题，您必须简化并逐步解决，找到解决方案将更加容易。

例如只需加入两个表

SELECT Orders.OrderID, Customers.CustomerName, Orders.OrderDate
FROM Orders
INNER JOIN Customers ON Orders.CustomerID=Customers.CustomerID;

按具有JOIN，LEFT JOIN和UNION的子查询排序

3 个答案: