SQL select 不同于串联列

Question

这个查询几乎可以满足我的要求

SELECT staging.dbo.ITEM_CODES.ITEM_CODE, MAX(dbo.OC_VDAT_AUX.UDL40) AS SAMPLEDATE,
           CONCAT(RTRIM(dbo.OC_VDATA.UDL1), RTRIM(dbo.OC_VDATA.UDL6)) as LinkID
FROM dbo.OC_VDATA 
    INNER JOIN dbo.OC_VDAT_AUX ON dbo.OC_VDATA.PARTNO = dbo.OC_VDAT_AUX.PARTNOAUX AND dbo.OC_VDATA.DATETIME = dbo.OC_VDAT_AUX.DATETIMEAUX 
    INNER JOIN stagingPLM.dbo.ITEM_CODES ON LEFT(dbo.OC_VDATA.PARTNO, 12) = staging.dbo.ITEM_CODES.SPEC_NO 
    AND LEFT(dbo.OC_VDAT_AUX.PARTNOAUX, 12) = stagingPLM.dbo.ITEM_CODES.SPEC_NO 
    INNER JOIN stagingPLM.dbo.PLANTS ON dbo.OC_VDATA.UDL1 = staging.dbo.PLANTS.PLANT_CODE
WHERE  (CONVERT(DATETIME, dbo.OC_VDAT_AUX.UDL40) > DATEADD(day, - 30, GETDATE()))
GROUP BY CONCAT(RTRIM(dbo.OC_VDATA.UDL1), RTRIM(dbo.OC_VDATA.UDL6)),staging.dbo.ITEM_CODES.ITEM_CODE

样本 Table 由查询生成：

我试图实现的最终结果是每个唯一 LinkID 的最新 ITEM_CODE 请注意 table 中的第一行和最后一行。最后一行不应被查询拉出。我如何修改此查询以实现此目的？我在 select 和 where 语句中尝试了 DISTINCT 和子查询的各种放置。

Answer 1

我会用 ROW_NUMBER window 函数和 CTE.

解决方法可以这样：

WITH FilterCTE AS
(
    SELECT staging.dbo.ITEM_CODES.ITEM_CODE, MAX(dbo.OC_VDAT_AUX.UDL40) AS SAMPLEDATE,
               CONCAT(RTRIM(dbo.OC_VDATA.UDL1), RTRIM(dbo.OC_VDATA.UDL6)) AS LinkID,
               ROW_NUMBER() OVER (PARTITION BY CONCAT(RTRIM(dbo.OC_VDATA.UDL1), RTRIM(dbo.OC_VDATA.UDL6)) ORDER BY MAX(dbo.OC_VDAT_AUX.UDL40)) AS RowNumber
    FROM dbo.OC_VDATA 
        INNER JOIN dbo.OC_VDAT_AUX ON dbo.OC_VDATA.PARTNO = dbo.OC_VDAT_AUX.PARTNOAUX AND dbo.OC_VDATA.DATETIME = dbo.OC_VDAT_AUX.DATETIMEAUX 
        INNER JOIN stagingPLM.dbo.ITEM_CODES ON LEFT(dbo.OC_VDATA.PARTNO, 12) = staging.dbo.ITEM_CODES.SPEC_NO 
        AND LEFT(dbo.OC_VDAT_AUX.PARTNOAUX, 12) = stagingPLM.dbo.ITEM_CODES.SPEC_NO 
        INNER JOIN stagingPLM.dbo.PLANTS ON dbo.OC_VDATA.UDL1 = staging.dbo.PLANTS.PLANT_CODE
    WHERE  (CONVERT(DATETIME, dbo.OC_VDAT_AUX.UDL40) > DATEADD(day, - 30, GETDATE()))
    GROUP BY CONCAT(RTRIM(dbo.OC_VDATA.UDL1), RTRIM(dbo.OC_VDATA.UDL6)),staging.dbo.ITEM_CODES.ITEM_CODE
)
SELECT *
FROM FilterCTE
WHERE RowNumber = 1

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sql-server-2016