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:

IF NOT EXISTS (SELECT * FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME = 'Numbers')
BEGIN
     CREATE TABLE dbo.Numbers
    (
        Num INT NOT NULL 
        CONSTRAINT [PKC__Numbers__Num] PRIMARY KEY CLUSTERED (Num) on [PRIMARY]
    )
    ;WITH Nbrs_3( n ) AS ( SELECT 1 UNION SELECT 0 ),
          Nbrs_2( n ) AS ( SELECT 1 FROM Nbrs_3 n1 CROSS JOIN Nbrs_3 n2 ),
          Nbrs_1( n ) AS ( SELECT 1 FROM Nbrs_2 n1 CROSS JOIN Nbrs_2 n2 ),
          Nbrs_0( n ) AS ( SELECT 1 FROM Nbrs_1 n1 CROSS JOIN Nbrs_1 n2 ),
          Nbrs  ( n ) AS ( SELECT 1 FROM Nbrs_0 n1 CROSS JOIN Nbrs_0 n2 )
     
    INSERT INTO dbo.Numbers(Num)
    SELECT n
    FROM ( SELECT ROW_NUMBER() OVER (ORDER BY n)
          FROM Nbrs ) D ( n )
         WHERE n <= 50000 ;
END

Numbers tables are an invaluable addition to your toolset. To quote Adam Machanic:

Numbers tables are truly invaluable. I use them all of the time for string manipulation, simulating window functions, populating test tables with lots of data, eliminating cursor logic, and many other tasks that would be incredibly difficult without them.

Is using a table of numbers a hack, as I've seen some people claim? No. Show me another way to efficiently do all of the things a numbers table can. Does it waste space? No. The script below will use up around 900 KB of disk space in each database. That's absolutely nothing. You'll end up getting millions, maybe billions of times the disk space investment back in terms of ease of development and time saved. http://sqlblog.com/blogs/adam_machanic/archive/2006/07/12/you-require-a-numbers-table.aspx

Enjoy!