如何只能选择改变的值

很难，即使我的英文，所以我要告诉我想要什么，通过下面的例子来解释：如何只能选择改变的值

比如我有一个表，如：

日期ID瓦尔

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

所以我要注册只改变值喜欢：

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

也许有人为例或任何想法，我怎么能够实现这些改变，谢谢。

来源

2011-03-03 Cynede

您是否在尝试查找ID和Val的所有唯一组合？ – 2011-03-03 05:59:31

@Abe Miessler不，我修正了一个例子，我想注册这个变化。 – Cynede 2011-03-03 06:10:00

像下面这样的东西可能会诀窍。

;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

来源

2011-03-03 06:16:55 Thomas

这真是太棒了，非常感谢您的解答！ – Cynede 2011-03-03 06:46:34

如何只能选择改变的值

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