Question

I’ve been working on a stored procedure and hit a point where I have two really horrid lines. Is there a way to re-write this in a clearer way within the stored procedure? If not, how would I go about creating a function to do this?

, REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(l.tenant_trading_name,'~','-'), '"','-'), '#','-'), '%','-'), '*','-'), ':','-'), '<','-'), '>','-'), '?','-'), '/','-'), '\','-'), '{','-'), '|','-'), '}','-') as trading_name
    ,   REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(l.suite_name,'&','-'), '~','-'), '"','-'), '#','-'), '%','-'), '*','-'), ':','-'), '<','-'), '>','-'), '?','-'), '/','-'), '\','-'), '{','-'), '|','-'), '}','-') as suite_name

Answer 1

Well you could simply have a function that does the dirty work for you:

CREATE FUNCTION dbo.CleanCharacters
(
  @InputString VARCHAR(64),
  @UseAmp BIT
)
RETURNS VARCHAR(64)
AS
BEGIN
  RETURN(SELECT REPLACE(REPLACE(REPLACE(...REPLACE(
      @InputString, CASE WHEN @UseAmp = 1 THEN '&' ELSE '-' END, '-'),
      '~', '')...etc etc...)))
  );
END
GO

Then you can say:

SELECT dbo.CleanCharacters(l.tenant_trading_name, 0),
dbo.CleanCharacters(l.suite_name, 1) FROM ...

This at least abstracts the ugly REPLACE() calls out of the procedure.

(Note that I didn’t quite parse the entire line to see if there were other differences but it seemed to me that the only difference was the suite_name couldn’t have an & but the trading name could.)

Another way would be to store your “bad” characters in a table, making maintenance of those replacements a little easier (and once the table is populated, making the function much cleaner as well).

CREATE TABLE dbo.DirtyCharacters(x CHAR(1));

INSERT dbo.DirtyCharacters SELECT '~' 
  UNION ALL SELECT '&' 
  UNION ALL SELECT '*'
-- ...
;

Now you can have your function simply say:

ALTER FUNCTION dbo.CleanCharacters
(
  @InputString VARCHAR(64),
  @UseAmp BIT
)
RETURNS VARCHAR(64)
AS
BEGIN
  SELECT @InputString = REPLACE(@InputString, x, '-')
    FROM dbo.DirtyCharacters 
    WHERE x <> CASE WHEN @UseAmp = 1 THEN '' ELSE '&' END;

  RETURN (@InputString);
END
GO