sql - 如何按月份和业务区域只选择最终值？

Question

我有下表，我想根据业务领域只选择上个月。

这些原始表:

fk_month    fk_business_area
201706       8
201707       25
201707       27
201707       9
201707       8
201707       28
201707       26
201708       9

选择后，我想要这个结果:

fk_month    fk_business_area
201707      25
201707      27
201707      8
201707      28
201707      26
201708      9

问候。

Answer 1

你可以做一个 MAX() 聚合:

Select   Max(fk_month) As fk_month,
         fk_business_area
From     TheseOriginalTable
Group By fk_business_area

您还可以使用窗口函数来查找最近的一个:

;With Cte As
(
    Select  *,
            Row_Number() Over (Partition By fk_business_area Order By fk_month Desc) RN
    From    TheseOriginalTable
)
Select  fk_month, fk_business_area
From    Cte
Where   RN = 1