Following script by Ashish Jain fixed my issue 🙂

CREATE FUNCTION dbo.DistinctList

(

@List VARCHAR(MAX),

@Delim CHAR

)

RETURNS

VARCHAR(MAX)

AS

BEGIN

DECLARE @ParsedList TABLE

(

Item VARCHAR(MAX)

)

DECLARE @list1 VARCHAR(MAX), @Pos INT, @rList VARCHAR(MAX)

SET @list = LTRIM(RTRIM(@list)) + @Delim

SET @pos = CHARINDEX(@delim, @list, 1)

WHILE @pos > 0

BEGIN

SET @list1 = LTRIM(RTRIM(LEFT(@list, @pos - 1)))

IF @list1 <> ''

INSERT INTO @ParsedList VALUES (CAST(@list1 AS VARCHAR(MAX)))

SET @list = SUBSTRING(@list, @pos+1, LEN(@list))

SET @pos = CHARINDEX(@delim, @list, 1)

END

SELECT @rlist = COALESCE(@rlist+',','') + item

FROM (SELECT DISTINCT Item FROM @ParsedList) t

RETURN @rlist

END

GO

SELECT dbo.DistinctList('342,34,456,34,3454,456,aa,bb,cc,aa',',') DistinctList

GO