SQL Server：在包含子句的派生表上加入？

Question

我想加入包含子句的子查询 /派生表 ROW_NUMBER() = 1）。在Teradata中，类似的东西可以正常工作，但Teradata使用 QUALIFY ROW_NUMBER() = 1 而不是条款。

这是我尝试加入的尝试：

-- want to join row with max StartDate on JobModelID
INNER JOIN (
    WITH AllRuns AS (
        SELECT *,
            ROW_NUMBER() OVER (PARTITION BY JobModelID ORDER BY StartDate DESC) AS RowNumber
        FROM Runs
    )
    SELECT * FROM AllRuns WHERE RowNumber = 1
) Runs
ON JobModels.JobModelID = Runs.JobModelID

我究竟做错了什么？

Answer 1

添加连接条件的效率可能较低，但通常对我来说很好。

INNER JOIN (
    SELECT *,
           ROW_NUMBER() OVER 
           (PARTITION BY JobModelID 
           ORDER BY StartDate DESC) AS RowNumber
      FROM Runs
    ) Runs
ON JobModels.JobModelID = Runs.JobModelID 
AND Runs.RowNumber = 1

Answer 2

您可以使用多个条款。就像是

;WITH AllRuns AS ( 
        SELECT  *, 
                ROW_NUMBER() OVER (PARTITION BY JobModelID ORDER BY StartDate DESC) AS RowNumber 
        FROM    Runs 
),
Runs AS(
        SELECT  * 
        FROM    AllRuns 
        WHERE   RowNumber = 1
)

SELECT  *
FROM    ... INNER JOIN ( 
        Runs ON JobModels.JobModelID = Runs.JobModelID 

有关用法/结构/规则的更多详细信息，请参见 使用common_table_expression（Transact-SQL）