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我需要在下面的代码中加入一个名为 IB 的表。我需要从 IB 中提取以下字段：QOO、QOH、QCM 和 AVG。JOIN 条件为 IJ.IJITEM = IB.IBITEM 和 IJ.IJLOC = IB.IBLOC 

;WITH cte AS 
    (
      SELECT IJLOC, IJITEM, IJDATE, IJLCGT,
        rn = ROW_NUMBER() OVER (PARTITION BY IJITEM, IJLOC ORDER BY IJDATE DESC)
      FROM dbo.IJ
    )
    SELECT IJLOC, IJITEM, IJDATE, IJLCGT
    FROM cte WHERE rn = 1;
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2 回答 2

1

一种比在最终 SELECT 中将 IB 表加入到“cte”更复杂的方法是使用当前表作为表嵌套另一个 CTE。例如：

;WITH cte AS 
(
    SELECT IJLOC, IJITEM, IJDATE, IJLCGT,
    rn = ROW_NUMBER() OVER (PARTITION BY IJITEM, IJLOC ORDER BY IJDATE DESC)
    FROM dbo.IJ
),
filtered AS (
    SELECT IJLOC, IJITEM, IJDATE, IJLCGT
    FROM cte
    WHERE rn = 1
)
SELECT  ib.QOO, ib.QOH, ib.QCM, ib.[AVG]
FROM    ib
INNER JOIN filtered
        ON filtered.IJITEM = IB.IBITEM
        AND filtered.IJLOC = IB.IBLOC

另一种选择，取决于查询优化器如何处理所有表之间的 JOIN，如果您不需要从 IJ 表中返回任何字段，则将 CTE 的结果插入到临时表中，然后 JOIN到那个。例如：

CREATE TABLE #Temp (IJITEM DataType, IJLOC DataType)

;WITH cte AS 
(
    SELECT IJLOC, IJITEM, IJDATE, IJLCGT,
    rn = ROW_NUMBER() OVER (PARTITION BY IJITEM, IJLOC ORDER BY IJDATE DESC)
    FROM dbo.IJ
)
INSERT INTO #Temp (IJITEM, IJLOC)
    SELECT IJITEM, IJLOC
    FROM cte
    WHERE rn = 1;

SELECT  ib.QOO, ib.QOH, ib.QCM, ib.[AVG]
FROM    ib
INNER JOIN #Temp tmp
        ON tmp.IJITEM = IB.IBITEM
        AND tmp.IJLOC = IB.IBLOC
于 2013-11-05T18:52:34.653 回答
0 
;
WITH    cte
          AS ( SELECT   IJLOC ,
                        IJITEM ,
                        IJDATE ,
                        IJLCGT ,
                        rn = ROW_NUMBER() OVER ( PARTITION BY IJITEM, IJLOC ORDER BY IJDATE DESC )
               FROM     dbo.IJ
             )
    SELECT  IJLOC ,
            IJITEM ,
            IJDATE ,
            IJLCGT ,
            IB.QOO ,
            IB.QOH ,
            IB.QCM ,
            IB.[AVG]
    FROM    cte
            INNER JOIN IB ON cte.IJITEM = IB.IBITEM
                             AND cte.IJLOC = IB.IBLOC
    WHERE   cte.rn = 1 ;
于 2013-11-05T19:00:16.160 回答