SQL Server 2012 LocalDB中的左外部聯接不起作用？

Question

使用SQL Server 2012（LocalDB），我有三個表：

BESEXT.COMPUTER
BESEXT.ANALYSIS_PROPERTY
BESEXT.ANALYSIS_PROPERTY_RESULT

這些包含以下信息：

• BESEXT.COMPUTER：計算機ID和計算機名稱之間的映射
• BESEXT.ANALYSIS_PROPERTY：可以映射到計算機的屬性列表
• BESEXT.ANALYSIS_PROPERTY_RESULT：計算機的屬性值列表

首先，我執行以下查詢：

SELECT
    AR.ComputerID,
    AP.Name,
    AR.Value
FROM BESEXT.ANALYSIS_PROPERTY_RESULT AR
JOIN BESEXT.ANALYSIS_PROPERTY AP ON AP.ID = AR.PropertyID
    AND AP.ID IN (1672, 1673, 1674)
ORDER BY AR.ComputerID, AP.Name

結果如下：

ComputerID  Name                Value
----------  ----                -----
595640      DisplayName         Windows 8.1 x64 - Mobile Device Image - v3.2 
595640      SequenceName        Windows 8.1 x64 - Mobile Device Image
595640      SequenceVersion     3.2
631459      DisplayName         Windows 8.1 x64 - Mobile Device Image - v3.2 
631459      SequenceName        Windows 8.1 x64 - Mobile Device Image
631459      SequenceVersion     3.2

在BESEXT.COMPUTER中，我具有以下值：

ID  ComputerID  ComputerName
--  ----------  ------------
1   595640      PO121203866
2   631459      PO121201739
3   1101805     PO121201100

我想在第一次選擇時對所有計算機對象執行左外部聯接，以便知道哪些計算機沒有價值。

因此，首先，我對先前的選擇進行簡單的內部聯接：

SELECT
    C.ComputerName,
    R.ComputerID,
    R.Name,
    R.Value
FROM (
    SELECT
        AR.ComputerID,
        AP.Name,
        AR.Value
    FROM BESEXT.ANALYSIS_PROPERTY_RESULT AR
    JOIN BESEXT.ANALYSIS_PROPERTY AP ON AP.ID = AR.PropertyID
        AND AP.ID IN (1672, 1673, 1674)
) R
JOIN BESEXT.COMPUTER C ON C.ComputerID = R.ComputerID
ORDER BY R.ComputerID, R.Name

可以預見的是，得出以下結果集：

ComputerName    ComputerID  Name            Value
------------    ----------  ----            -----
PO121203866     595640      DisplayName     Windows 8.1 x64 - Mobile Device Image - v3.2 
PO121203866     595640      SequenceName    Windows 8.1 x64 - Mobile Device Image
PO121203866     595640      SequenceVersion 3.2
PO121201739     631459      DisplayName     Windows 8.1 x64 - Mobile Device Image - v3.2 
PO121201739     631459      SequenceName    Windows 8.1 x64 - Mobile Device Image
PO121201739     631459      SequenceVersion 3.2

現在，作為大結局，讓我們做LEFT OUTER JOIN ：

SELECT
    C.ComputerName,
    R.ComputerID,
    R.Name,
    R.Value
FROM (
    SELECT
        AR.ComputerID,
        AP.Name,
        AR.Value
    FROM BESEXT.ANALYSIS_PROPERTY_RESULT AR
    JOIN BESEXT.ANALYSIS_PROPERTY AP ON AP.ID = AR.PropertyID
        AND AP.ID IN (1672, 1673, 1674)
) R
-- LEFT OUTER JOIN ADDED HERE! 
LEFT OUTER JOIN BESEXT.COMPUTER C ON C.ComputerID = R.ComputerID
ORDER BY R.ComputerID, R.Name

這將產生與內部聯接完全相同的結果集 ！

這不是我想要的，也根本不是我所期望的。 現在已經很晚了，我基本上是在失眠的情況下做一些工作，但是我認為這是盡可能簡單的外部連接示例，對吧？ 我希望通過外部聯接實現的結果是：

ComputerName    ComputerID  Name            Value
PO121203866     595640      DisplayName     Windows 8.1 x64 - Mobile Device Image - v3.2 
PO121203866     595640      SequenceName    Windows 8.1 x64 - Mobile Device Image
PO121203866     595640      SequenceVersion 3.2
PO121201739     631459      DisplayName     Windows 8.1 x64 - Mobile Device Image - v3.2 
PO121201739     631459      SequenceName    Windows 8.1 x64 - Mobile Device Image
PO121201739     631459      SequenceVersion 3.2
PO121201100     NULL        NULL            NULL
PO121201100     NULL        NULL            NULL
PO121201100     NULL        NULL            NULL

PS：說實話，我正在尋找的結果更像這樣，但我覺得這將是完全不同的問題：

ComputerName    Name            Value
------------    ----            -----
PO121203866     DisplayName     Windows 8.1 x64 - Mobile Device Image - v3.2 
PO121203866     SequenceName    Windows 8.1 x64 - Mobile Device Image
PO121203866     SequenceVersion 3.2
PO121201739     DisplayName     Windows 8.1 x64 - Mobile Device Image - v3.2 
PO121201739     SequenceName    Windows 8.1 x64 - Mobile Device Image
PO121201739     SequenceVersion 3.2
PO121201100     DisplayName     NULL
PO121201100     SequenceName    NULL
PO121201100     SequenceVersion NULL

Answer 1

您要查找的查詢可以這樣簡單地編寫：

SELECT ComputerName, A.ComputerID, Name, Value FROM BESEXT.COMPUTER A
CROSS JOIN (SELECT * FROM BESEXT.ANALYSIS_PROPERTY WHERE ID BETWEEN 1672 AND 1674) B
LEFT JOIN BESEXT.ANALYSIS_PROPERTY_RESULT C ON A.ComputerId = C.ComputerId AND B.ID = C.PropertyId
ORDER BY ComputerId, Name

首先獲取您關心的所有計算機屬性組合：

SELECT * FROM BESEXT.COMPUTER A
CROSS JOIN (SELECT * FROM BESEXT.ANALYSIS_PROPERTY WHERE ID BETWEEN 1672 AND 1674) B

這樣會產生結果：

ID  ComputerId  ComputerName  ID    Name
--  ----------  ------------  --    ----
1   595640      PO121203866   1672  DisplayName
2   631459      PO121201739   1672  DisplayName
3   1101805     PO121201100   1672  DisplayName
1   595640      PO121203866   1673  SequenceName
2   631459      PO121201739   1673  SequenceName
3   1101805     PO121201100   1673  SequenceName
1   595640      PO121203866   1674  SequenceVersion
2   631459      PO121201739   1674  SequenceVersion
3   1101805     PO121201100   1674  SequenceVersion

從那里，您只需在BESEXT.ANALYSIS_PROPERTY_RESULT上執行左BESEXT.ANALYSIS_PROPERTY_RESULT即可獲取您的值，並包含ORDER BY子句對其進行排序。

Answer 2

您可以使用交叉連接為所有計算機設置屬性，然后使用左連接連接到已設置值的計算機的實際屬性值，以實現此目的：

SELECT * FROM (
    SELECT
       C.ComputerName,
       C.ComputerID,
       AP.Name,
       AP.ID
    FROM BESEXT.COMPUTER C
    CROSS JOIN BESEXT.ANALYSIS_PROPERTY AP
    WHERE AP.ID IN (1672, 1673, 1674)
) AP
LEFT JOIN BESEXT.ANALYSIS_PROPERTY_RESULT AR  
ON AP.ComputerID = AR.ComputerID AND AP.ID = AR.PropertyID
ORDER BY AP.ComputerName DESC, AP.Name

Answer 3

作為LOJ，會是這樣嗎？

SELECT
    R.ComputerName,
    C.ComputerID,
    C.Name,
    C.Value
FROM BESEXT.COMPUTER R
-- LEFT OUTER JOIN ADDED HERE! 
LEFT OUTER JOIN 
(
    SELECT
        AR.ComputerID,
        AP.Name,
        AR.Value
    FROM BESEXT.ANALYSIS_PROPERTY_RESULT AR
    JOIN BESEXT.ANALYSIS_PROPERTY AP ON AP.ID = AR.PropertyID
        AND AP.ID IN (1672, 1673, 1674)
) C 
  ON C.ComputerID = R.ComputerID
ORDER BY C.ComputerID, C.Name