Question

还有另一种写方法吗？

SELECT src.ID, factDeviceBuild.ID
    FROM #factDeviceBuild as src
    INNER JOIN AppsFlyer.FactDeviceBuild AS factDeviceBuild
    ON src.[DimDevice_Id] = factDeviceBuild.[DimDevice_Id] AND
        src.[DimDeviceModel_Id] = factDeviceBuild.[DimDeviceModel_Id] AND
        src.[DimPlatform_Id] = factDeviceBuild.[DimPlatform_Id] AND
        src.[DimOSVersion_Id] = factDeviceBuild.[DimOSVersion_Id] AND
        src.[DimSDKVersion_Id] = factDeviceBuild.[DimSDKVersion_Id] AND
        src.[DimCarrier_Id] = factDeviceBuild.[DimCarrier_Id] AND
        src.[DimOperator_Id] = factDeviceBuild.[DimOperator_Id]

我一直在尝试像这样做一些不同的事情（不起作用）

SELECT *, factDeviceBuild.ID
    FROM #factDeviceBuild
    WHERE EXISTS (
        SELECT [DimDevice_Id], [DimDeviceModel_Id], [DimPlatform_Id],
            [DimOSVersion_Id], [DimSDKVersion_Id], [DimCarrier_Id],
            [DimOperator_Id]
        FROM AppsFlyer.FactDeviceBuild AS factDeviceBuild
        )

或类似的方法（也不起作用）：

SELECT factDeviceBuild.ID, 
        factDeviceBuild.[ID]
    FROM (
        SELECT [DimDevice_Id], [DimDeviceModel_Id], [DimPlatform_Id],
            [DimOSVersion_Id], [DimSDKVersion_Id], [DimCarrier_Id],
            [DimOperator_Id]
        FROM AppsFlyer.FactDeviceBuild AS factDeviceBuild
        INTERSECT
        SELECT [DimDevice_Id], [DimDeviceModel_Id], [DimPlatform_Id],
            [DimOSVersion_Id], [DimSDKVersion_Id], [DimCarrier_Id],
            [DimOperator_Id]
        FROM AppsFlyer.#factDeviceBuild AS factDeviceBuild
    ) AS A

我只是在进行一些查询调整。 EXCEPT和INTERSECT尤其有趣，因为它们对待NULLS的方式。

很明显，我可以使用CROSS JOIN或OUTER JOIN来构造我的INNER JOIN表格草稿，但是我看不到那里有什么特别的收获。

Answer 1

我相信您正在寻找这样的东西：

SELECT src.ID, fact.ID
FROM #factDeviceBuild as src
INNER JOIN AppsFlyer.FactDeviceBuild AS fact
ON EXISTS (
    SELECT src.DimDevice_Id, src.DimDeviceModel_Id, src.DimPlatform_Id,
        src.DimOSVersion_Id, src.DimSDKVersion_Id, src.DimCarrier_Id,
        src.DimOperator_Id
    INTERSECT
    SELECT fact.DimDevice_Id, fact.DimDeviceModel_Id, fact.DimPlatform_Id,
        fact.DimOSVersion_Id, fact.DimSDKVersion_Id, fact.DimCarrier_Id,
        fact.DimOperator_Id
)

使用这种INTERSECT语法（而不是通常的条件）具有将NULL-视为相同值的优点。例如，如果仅DimCarrier_Id和DimOperator_Id列允许NULL，则等效条件将是：

SELECT src.ID, fact.ID
FROM #factDeviceBuild as src
INNER JOIN AppsFlyer.FactDeviceBuild AS fact
ON src.DimDevice_Id = fact.DimDevice_Id AND
    src.DimDeviceModel_Id = fact.DimDeviceModel_Id AND
    src.DimPlatform_Id = fact.DimPlatform_Id AND
    src.DimOSVersion_Id = fact.DimOSVersion_Id AND
    src.DimSDKVersion_Id = fact.DimSDKVersion_Id AND
    (src.DimCarrier_Id = fact.DimCarrier_Id OR src.DimCarrier_Id IS NULL AND fact.DimCarrier_Id IS NULL) AND
    (src.DimOperator_Id = fact.DimOperator_Id OR src.DimOperator_Id IS NULL AND fact.DimOperator_Id IS NULL)

Answer 2

关注相同

SELECT src.ID, factDeviceBuild.ID
    FROM #factDeviceBuild as src, AppsFlyer.FactDeviceBuild AS factDeviceBuild
    WHERE
        src.[DimDevice_Id] = factDeviceBuild.[DimDevice_Id] AND
        src.[DimDeviceModel_Id] = factDeviceBuild.[DimDeviceModel_Id] AND
        src.[DimPlatform_Id] = factDeviceBuild.[DimPlatform_Id] AND
        src.[DimOSVersion_Id] = factDeviceBuild.[DimOSVersion_Id] AND
        src.[DimSDKVersion_Id] = factDeviceBuild.[DimSDKVersion_Id] AND
        src.[DimCarrier_Id] = factDeviceBuild.[DimCarrier_Id] AND
        src.[DimOperator_Id] = factDeviceBuild.[DimOperator_Id]

Answer 3

没有数据或预期结果的可视化，我的猜测是您需要将7个id类型“取消透视”成更少的列，从而降低了连接语法的复杂性。例如：

select
     src.id, f.fact_id, ca.id_type, ca.id_value
from #factDeviceBuild as src
cross apply (
    values
       ('DimDevice_Id',src.[DimDevice_Id])
      ,('DimDeviceModel_Id',src.[DimDeviceModel_Id])
      ,('DimPlatform_Id',src.[DimPlatform_Id])
      ,('DimOSVersion_Id',src.[DimOSVersion_Id])
      ,('DimSDKVersion_Id',src.[DimSDKVersion_Id])
      ,('DimCarrier_Id',src.[DimCarrier_Id])
      ,('DimOperator_Id',src.[DimOperator_Id])
    ) ca (id_type, id_value)
inner join (
    select
         fact.id fact_id, ca.id_type, ca.id_value
    from AppsFlyer.FactDeviceBuild AS fact
    cross apply (
        values
           ('DimDevice_Id',fact.[DimDevice_Id])
          ,('DimDeviceModel_Id',fact.[DimDeviceModel_Id])
          ,('DimPlatform_Id',fact.[DimPlatform_Id])
          ,('DimOSVersion_Id',fact.[DimOSVersion_Id])
          ,('DimSDKVersion_Id',fact.[DimSDKVersion_Id])
          ,('DimCarrier_Id',fact.[DimCarrier_Id])
          ,('DimOperator_Id',fact.[DimOperator_Id])
        ) ca (id_type, id_value)
    where ca.id_value IS NOT NULL
    ) as f on ca.id_type = f.id_type and ca.id_value = f.id_value

注意，我没有使用TSQL的“ unpivot”功能，因为我更喜欢上面看到的语法。使用此apply/values语法时，没有其他性能劣势。

NB：所有这些id类型列中的所有7个必须是“兼容”数据类型，“ unpivot”才能正常工作。例如，全部7为整数，这会使id_value成为整数列。

从没有联接语法的联接中获取特定列？

3 个答案: