DELIMITER //
CREATE FUNCTION stripChars(theString varchar(255), blackList varchar(255)) RETURNS varchar(255) DETERMINISTIC 
BEGIN
	DECLARE i INT DEFAULT 1;
	DECLARE response VARCHAR(255) DEFAULT '';
	DECLARE theChar CHAR(1);

	WHILE i <= CHAR_LENGTH(theString) DO
		SET theChar := SUBSTRING(theString, i, 1);
		IF LOCATE(theChar, blackList) = 0 THEN SET response := CONCAT(response, theChar); END IF;
		SET i := i + 1;
	END WHILE;
	RETURN response;
END//
DELIMITER ;