SQL點滴3—一個簡單的字符串分割函數(shù)

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO

/*by kudychen 2011-9-28 */
CREATE function [dbo].[SplitString]
(    
  @Input nvarchar(max), --input string to be separated    
  @Separator nvarchar(max)=',', --a string that delimit the substrings in the input string    
  @RemoveEmptyEntries bit=1 --the return value does not include array elements that contain an empty string
)
returns @TABLE table 
(    
  [Id] int identity(1,1),    
  [Value] nvarchar(max)) 
as
begin     
  declare @Index int, @Entry nvarchar(max)    
  set @Index = charindex(@Separator,@Input)    

  while (@Index>0)    
  begin        
    set @Entry=ltrim(rtrim(substring(@Input, 1, @Index-1)))                

      if (@RemoveEmptyEntries=0) or (@RemoveEmptyEntries=1 and @Entry<>'')            
        begin                
          insert into @TABLE([Value]) Values(@Entry)            
        end        

        set @Input = substring(@Input, @Index+datalength(@Separator)/2, len(@Input))        
        set @Index = charindex(@Separator, @Input)    
  end        

  set @Entry=ltrim(rtrim(@Input))    
  if (@RemoveEmptyEntries=0) or (@RemoveEmptyEntries=1 and @Entry<>'')        
    begin            
      insert into @TABLE([Value]) Values(@Entry)        
    end    
return

end

declare @str1 varchar(max), @str2 varchar(max), @str3 varchar(max)

set @str1 = '1,2,3'
set @str2 = '1###2###3'
set @str3 = '1###2###3###'

select [Value] from [dbo].[SplitString](@str1, ',', 1)
select [Value] from [dbo].[SplitString](@str2, '###', 1)
select [Value] from [dbo].[SplitString](@str3, '###', 0)