MySQL needs this in a datebase:

Code:
CREATE TABLE IF NOT EXISTS `players` (
  `id` int(10) NOT NULL AUTO_INCREMENT,
  `user` varchar(32) DEFAULT NULL,
  `pass` varchar(32) DEFAULT NULL,
  `money` int(10) DEFAULT NULL,
  `xp` int(10) DEFAULT NULL,
  `kills` int(10) DEFAULT NULL,
  `headshots` int(10) DEFAULT NULL,
  `melee_kills` int(10) DEFAULT NULL,
  `longest_killstreak` int(10) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;


DELIMITER $$


DROP FUNCTION IF EXISTS statsDeltaMoney$$


CREATE FUNCTION statsDeltaMoney (id_ INT, money_ INT)
RETURNS INT
DETERMINISTIC
BEGIN
    DECLARE ret INT;
    SET ret = NULL;
    UPDATE players SET money=IFNULL(money,0)+money_ WHERE id = id_;
    SELECT money FROM players WHERE id = id_ INTO ret;
    RETURN ret;
END$$

DELIMITER ;

SELECT statsDeltaMoney(5, 10) AS newMoney;







DELIMITER $$


DROP FUNCTION IF EXISTS statsDeltaXP$$


CREATE FUNCTION statsDeltaXP (id_ INT, xp_ INT)
RETURNS INT
DETERMINISTIC
BEGIN
    DECLARE ret INT;
    SET ret = NULL;
    UPDATE players SET xp=IFNULL(xp,0)+xp_ WHERE id = id_;
    SELECT xp FROM players WHERE id = id_ INTO ret;
    RETURN ret;
END$$

DELIMITER ;

SELECT statsDeltaXP(5, 10) AS newXP;