1  
   2  CREATE FUNCTION dbo.f_pad_before(@string VARCHAR(255), @desired_length INTEGER, @pad_character CHAR(1))
   3  RETURNS VARCHAR(255) AS  
   4  BEGIN
   5  
   6   -- Prefix the required number of spaces to bulk up the string and then replace the spaces with the desired character
   7   RETURN CASE
   8            WHEN LEN(@string) < @desired_length
   9              THEN REPLACE(SPACE(@desired_length - LEN(@string)), ' ', @pad_character) + @string
  10            ELSE @string
  11          END
  12  
  13  END
  14  GO

   1  
   2  SELECT dbo.f_pad_before('my string', 20, '-') AS [result], LEN(dbo.f_pad_before('my string', 20, '-')) AS [length]