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如何从SQL中的字符串中删除重复项

sql

我在SQL表中有一列,其中一些值是分开的bij "。此字符串中的某些值是重复的,我想删除。这是我的数据的示例:

---------------
| qw"qw"er"er |
---------------
| q"w"w"q     |
---------------
| f"k"s"g     |
---------------

现在,结果应替换所有重复项:

---------------
| qw"er       |
---------------
| q"w"        |
---------------
| f"k"s"g     |
---------------

所以首先我想分割字符串,然后删除重复项。有人可以帮我解决这个问题吗?


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2021-06-07

共1个答案

admin

具有解析功能的选项1

Declare @YourTable table (ID int,YourCol varchar(50))
Insert Into @YourTable values
(1,'qw"qw"er"er'),
(2,'q"w"w"q'),
(3,'f"k"s"g')

Select A.ID
      ,A.YourCol
      ,DeDuped   = Stuff((Select '"' + RetVal 
                           From (Select RetSeq=Min(RetSeq),RetVal 
                                  From  [dbo].[udf-Str-Parse](A.YourCol,'"') 
                                  Group By RetVal) P  
                            Order by 1 For XML Path('')),1,1,'') 
 From  @YourTable A

退货

ID  YourCol      DeDuped
1   qw"qw"er"er  qw"er
2   q"w"w"q      q"w
3   f"k"s"g      f"k"s"g

选项2:不带解析功能

Declare @YourTable table (ID int,YourCol varchar(50))
Insert Into @YourTable values
(1,'qw"qw"er"er'),
(2,'q"w"w"q'),
(3,'f"k"s"g')

Select A.ID
      ,A.YourCol
      ,DeDuped   = Stuff((Select '"' + RetVal 
                           From (Select RetSeq=Min(RetSeq),RetVal 
                                  From  (
                                            Select RetSeq = Row_Number() over (Order By (Select null))
                                                  ,RetVal = LTrim(RTrim(B.i.value('(./text())[1]', 'varchar(max)')))
                                            From  (Select x = Cast('<x>' + replace((Select replace(A.YourCol,'"','搂搂Split搂搂') as [*] For XML Path('')),'搂搂Split搂搂','</x><x>')+'</x>' as xml).query('.')) as A 
                                            Cross Apply x.nodes('x') AS B(i)
                                        ) P1
                                  Group By RetVal) P  
                            Order by RetSeq 
                            For XML Path('')),1,1,'') 
 From  @YourTable A

退货

ID  YourCol      DeDuped
1   qw"qw"er"er  qw"er
2   q"w"w"q      q"w
3   f"k"s"g      f"k"s"g

UDF(如果有兴趣)

CREATE FUNCTION [dbo].[udf-Str-Parse] (@String varchar(max),@Delimiter varchar(10))
Returns Table 
As
Return (  
    Select RetSeq = Row_Number() over (Order By (Select null))
          ,RetVal = LTrim(RTrim(B.i.value('(./text())[1]', 'varchar(max)')))
    From  (Select x = Cast('<x>' + replace((Select replace(@String,@Delimiter,'搂搂Split搂搂') as [*] For XML Path('')),'搂搂Split搂搂','</x><x>')+'</x>' as xml).query('.')) as A 
    Cross Apply x.nodes('x') AS B(i)
);
--Thanks Shnugo for making this XML safe
--Select * from [dbo].[udf-Str-Parse]('Dog,Cat,House,Car',',')
--Select * from [dbo].[udf-Str-Parse]('John Cappelletti was here',' ')
--Select * from [dbo].[udf-Str-Parse]('this,is,<test>,for,< & >',',')
--Performance On a 5,000 random sample -8K 77.8ms, -1M 79ms (+1.16), -- 91.66ms (+13.8)
2021-06-07