Question

I need a function to convert a string into only alphanumeric characters…

Meaning replace (empty) all other characters besides the standard 26 letters and 10 numbers with nothing/blank. And replace all spaces with a hyphen. An example would be like this:

From

   stack## overfl*w's s"te !s cool!

To

   stack-overflws-ste-s-cool

Any Suggestions?

Answer 1

CREATE FUNCTION dbo.StripNonAlphaNumerics
    (
      @s VARCHAR(255)
    )
    RETURNS VARCHAR(255)
    AS
    BEGIN
      DECLARE @p INT = 1, @n VARCHAR(255) = '', @c CHAR(1);
      SET @s = REPLACE(@s, ' ', '-');
      WHILE @p <= LEN(@s)
      BEGIN
        SET @c = SUBSTRING(@s, @p, 1);
        IF @c = '-' OR @c LIKE '[A-Za-z0-9]'
        BEGIN
          SET @n += @c;
        END 
        SET @p += 1;
      END
      RETURN(@n);
    END
    GO

Usage:

SELECT dbo.StripNonAlphaNumerics('tether-45(;$&@- ip');

Result:

tether-45--ip