SQL Server Central: URLEncode in TSQL

URLEncode - SQL Server Central
Call this function as you would any scalar UDF:
select dbo.URLEncode('K8%/fwO3L mEQ*.}')
This script requires a numbers tabel and assumes the following schema:
CREATE TABLE dbo.Numbers
(
Num INT NOT NULL
CONSTRAINT [PKC__Numbers__Num]
PRIMARY KEY CLUSTERED (Num) on [PRIMARY]
)

GO
SET ANSI_NULLS ON
GO

IF EXISTS (
SELECT 1
FROM dbo.sysobjects 
WHERE id = OBJECT_ID(N'[dbo].[URLEncode]') 
AND xtype IN (N'FN', N'IF', N'TF'))
BEGIN
DROP FUNCTION [dbo].[URLEncode]
END
GO

CREATE FUNCTION [dbo].[URLEncode] 
(@decodedString VARCHAR(4000))
RETURNS VARCHAR(4000)
AS
BEGIN
/*******************************************************************************************************
*   dbo.URLEncode 
*   Creator:       Robert Cary
*   Date:          03/18/2008
*
*   Notes:         
*                  
*
*   Usage:
select dbo.URLEncode('K8%/fwO3L mEQ*.}')
*   Modifications:   
*   Developer Name      Date        Brief description
*   ------------------- ----------- ------------------------------------------------------------
*   
********************************************************************************************************/

DECLARE @encodedString VARCHAR(4000)

IF @decodedString LIKE '%[^a-zA-Z0-9*-.!_]%' ESCAPE '!'
BEGIN
SELECT @encodedString = REPLACE(
COALESCE(@encodedString, @decodedString),
SUBSTRING(@decodedString,num,1),
'%' + SUBSTRING(master.dbo.fn_varbintohexstr(CONVERT(VARBINARY(1),ASCII(SUBSTRING(@decodedString,num,1)))),3,3))
FROM dbo.numbers 
WHERE num BETWEEN 1 AND LEN(@decodedString) AND SUBSTRING(@decodedString,num,1) like '[^a-zA-Z0-9*-.!_]' ESCAPE '!'
END
ELSE
BEGIN
SELECT @encodedString = @decodedString 
END

RETURN @encodedString

END
GO