CREATE FUNCTION [dbo].[Udf_TABLECOLUMNLIST]
( 
@strDataSet VARCHAR(4000)
) 
RETURNS @DST TABLE
(
	x SYSNAME
) 
AS

BEGIN
DECLARE @Idxb INT

	IF @strDataSet IS NULL RETURN -- a rowset having zero rows

	SET @Idxb=CHARINDEX(',',@strDataSet,1)

	WHILE @Idxb<>0
	BEGIN
		INSERT INTO @DST
		SELECT CAST(LTRIM(RTRIM(SUBSTRING(@strDataSet,1,@Idxb-1))) AS SYSNAME)

		SELECT @strDataSet=LTRIM(RTRIM(SUBSTRING(@strDataSet,@Idxb+1,LEN(@strDataSet)-@Idxb)))
		SET @Idxb=CHARINDEX(',',@strDataSet,1)
	END

	INSERT INTO @DST
	SELECT CAST(LTRIM(RTRIM(@strDataSet)) AS SYSNAME)

	RETURN 

END
GO

SELECT X, LEN(X) AS L FROM dbo.Udf_TABLECOLUMNLIST (' a , b ')
UNION ALL
SELECT X, LEN(X) AS L FROM dbo.Udf_TABLECOLUMNLIST (' c ')

declare @strDataSet as varchar(max);
declare @delimiter as varchar(10);
set @strDataSet='A,B,C,D,E';
set @delimiter =',';

declare @xml as xml;
set @xml = cast(('<X>'+replace(@strDataSet,@delimiter ,'</X><X>')+'</X>') as xml);
select N.value('.', 'sysname') as x from @xml.nodes('X') as T(N);

 ------------ XML Method  ------------

(9000 row(s) affected)

SQL Server Execution Times:
   CPU time = 235 ms,  elapsed time = 228 ms.


 ------------ Tally table method ------------

(9000 row(s) affected)

SQL Server Execution Times:
   CPU time = 156 ms,  elapsed time = 159 ms.