Sql 我想计算每行的最大金额

我正试图从第#行中获取最大金额，但我被这个查询卡住了

SELECT [Member_Id]
    ,[Picked_Date]
    ,[Location_Number]
    ,[Refill_Amount]
    ,[Total_Refills_Permitted]
    ,[Quantity_Dispensed]
    ,ROW_NUMBER() OVER (
        PARTITION BY Location_Number
        ,Member_Id ORDER BY Member_Id
            ,Picked_Date ASC
        ) AS Row#
FROM DummyTable
WHERE Row# IN (
        SELECT MAX(Row#)
        FROM DummyTable
        );

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您正在按

成员Id

进行分区和排序。虽然允许这样做，但这是非正统的，在

order by

中包含列除了使排序稍微慢一点，在某些情况下可能会妨碍索引的使用之外，没有任何作用

如果需要最新的行，则：

select dt.*
from (select dt.*,
             row_number() over (partition by Location_Number, Member_Id order by Picked_Date desc) as seqnum
      from dummytable dt
     ) dt
where seqnum = 1;

如果您仍然需要

行#

，它实际上就是计数。因此，这是另一种选择：

select dt.*
from (select dt.*,
             count(*) over (partition by Location_Number, Member_Id) as cnt,
             row_number() over (partition by Location_Number, Member_Id order by Picked_Date desc) as seqnum
      from dummytable dt
     ) dt
where seqnum = cnt;

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样本数据、期望的结果和数据库标记会有所帮助。