The best splitter for T-SQL is right here[/url] along with several tests. It will outperform any splitter using while loops or xml.

With it, you can replace your function to this. Note that it has a limit to 4000 unicode chars (8000 for non-unicode) to avoid the use of large data types and improve performance.

-- Split and concatenate back to string

CREATE FUNCTION [dbo].[Split_and_concatenate]

(

@STR NVARCHAR(4000)

,@delimiter CHAR(1)

)

RETURNS NVARCHAR(8000)

AS

BEGIN

SELECT STUFF( (SELECT '; ' + CASE Item WHEN '1' THEN '11'

WHEN '2' THEN '22'

ELSE '33' END

FROM dbo.[DelimitedSplitN4K](@str, @delimiter)

FOR XML PATH('')),1,2, '')