sql create function converting string to ascii integer

I want to sort records by its question no, e.g.: 1 , 2c , 10 , 12a. Is it good to convert them into sum of ascii code? if yes, what would be the error in the following code creating sql funcion? if no, what would be the better way to do that.

CREATE FUNCTION dbo.asciiCodeInteger (@string AS VARCHAR(3))
    RETURNS int
    AS
    BEGIN
      DECLARE @result int;
      DECLARE @char CHAR(1);

      SET @result = 0;

      WHILE LEN(@string) > 0
      BEGIN
        SET @char = LEFT(@string, 1);
        SET @result = @result + ASCII(@char);
        SET @string = SUBSTRING(@string, 2, LEN(@string));
      END
      RETURN (@result);
    END

via Chebli Mohamed