SQL SERVER Remove Duplicate Chars From String

CREATE FUNCTION dbo.REMOVE_DUPLICATE_INSTR

(@datalen_tocheck INT,@string VARCHAR(255))

RETURNS VARCHAR(255)
AS

BEGIN
DECLARE @str VARCHAR(255)
DECLARE @count INT
DECLARE @start INT


DECLARE @result VARCHAR(255)
DECLARE @end INT
SET @start=1

SET @end=@datalen_tocheck
SET @count=@datalen_tocheck
SET @str = @string

WHILE (@count <=255)
BEGIN

IF (@result IS NULL)
BEGIN
SET @result=”
END


SET @result=@result+SUBSTRING(@str,@start,@end)
SET @str=REPLACE(@str,SUBSTRING(@str,@start,@end),”)
SET @count=@count+@datalen_tocheck

END

RETURN @result

END

GO;


Usage:

SET CONCAT_NULL_YIELDS_NULL OFF

SELECT dbo.Remove_duplicate_instr(<CHARacter length OF a

duplicate SUBSTRING >,<string contain duplicate>)


Example:

To keep char set in a string unique and remove duplicate 3 char long string run this UDF as inline function.

SET CONCAT_NULL_YIELDS_NULL OFF

SELECT dbo.Remove_duplicate_instr(3,�f123456789123456456

Resultset:

123456789