CREATE FUNCTION [dbo].[fn_SplitString]
(
     @SourceString VARCHAR(MAX),
     @Seperator VARCHAR(25)=','
)

RETURNS @ResultTable

TABLE(
     [Position] INT IDENTITY(1,1),
     [Value] VARCHAR(MAX)
)

AS
BEGIN

     DECLARE @w_xml xml;

     SET @w_xml = N'<root><i>' + replace(@SourceString, @Seperator,'</i><i>') + '</i></root>';

     INSERT INTO @ResultTable
          ([Value])
     SELECT
          [i].value('.', 'VARCHAR(MAX)') AS Value
     FROM
          @w_xml.nodes('//root/i') AS [Items]([i]);

     RETURN;
END;
GO

SELECT * from dbo.fn_SplitString('Hello, thank you, bye!', ',')