Question

给出下表中的客户，类别，产品，日期和价值，

Customer | Category | Product | Date | Value | Single value
------------------------------------------------------------
Cust A   | Categ A  | SKU A   |010101|  100  |    100
------------------------------------------------------------
Cust A   | Categ A  | SKU B   |010101|  100  |   
------------------------------------------------------------
Cust A   | Categ B  | SKU C   |010101|  99   |    99
------------------------------------------------------------
Cust A   | Categ B  | SKU D   |010101|  99   |

如何填写“单值”列，只保留某个键组合的一个值（如客户，类别，日期）？

先谢谢

Answer 1

走出困境...这是使用CTE的一种方式，你可以修改它来做你想做的事。这会将[Single value]列设置为您所描述的配对的MAX()值，如partition by语句中所示。

;WITH CTE AS
(   SELECT  Customer, 
            Category, 
            Date,
            [Single value],
            MAX([Single value]) over(partition by Customer, Category, Date) as NewVal
    FROM    SomeTable
)

UPDATE  CTE
SET     [Single value] = NewVal

Answer 2

试试这个：

    update t set t.[Single value]=t.[Value] from 
    (
       select *,row_number()over(partition by Customer,Category, Date order by getdate()) as rn from #t
    ) as t where t.rn=1

如何使用具有特定字段组合的SQL在单个列中保留单值

2 个答案: