Question

即使用我的英语也难以解释，所以我将通过以下示例展示我想要的内容：

例如，我有一个像：

这样的表

日期 ID Val

SomeDate.... 1  0
SomeDate.... 2  0
SomeDate.... 2  0
SomeDate.... 1  0
SomeDate.... 1  0
SomeDate.... 1  1
SomeDate.... 1  1
SomeDate.... 2  1
SomeDate.... 1  0
SomeDate.... 2  0
SomeDate.... 1  0
SomeDate.... 1  1

所以我想只注册更改值，如：

SomeDate.... 1  1 //registered 0 -> 1 for ID 1
SomeDate.... 2  1 //registered 0 -> 1 for ID 2
SomeDate.... 1  0 //registered 1 -> 0 for ID 1
SomeDate.... 2  0 //registered 1 -> 0 for ID 2
SomeDate.... 1  1 //registered 0 -> 1 for ID 1

MS SQL SERVER 2008

也许某人有一个例子或任何关于如何实现这些变化的想法，谢谢。

Answer 1

以下内容可能会起到作用。

;With RankedDates As
    (
    Select T1.[Date], T1.ID, T1.Val
        , Row_Number() Over( Partition By T1.ID Order By T1.[Date] ) As Num
    From SourceTable As T1
    )
Select T1.[Date], T1.ID
    , T1.Val As InitialValue
    , T2.Val As ChangedToValue
    , T2.[Date] As ChangedDate
From RankedDates As T1
    Join RankedDates As T2
        On T2.ID = T1.ID
            And T2.Num = T1.Num + 1
            And T2.Val <> T1.Val
Order By T1.ID

如何仅选择更改值

1 个答案: