First Create the DB
CREATE TABLE IF NOT EXISTS `player_alias` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`uid` varchar(255) DEFAULT NULL,
`PlayerNames` text,
PRIMARY KEY (`id`),
UNIQUE KEY `uid` (`uid`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=4 ;
Then add this trigger
DELIMITER ;
DROP TRIGGER IF EXISTS `updateName`;
DELIMITER //
CREATE TRIGGER `updateName`
AFTER UPDATE ON player_data
FOR EACH ROW
BEGIN
#IF (NEW.PlayerName IS NULL OR NEW.PlayerName = '' OR NEW.PlayerName = OLD.PlayerName) THEN
IF (SELECT EXISTS(SELECT uid FROM player_alias WHERE `uid` = NEW.PlayerUID)) THEN
UPDATE player_alias SET PlayerNames = CONCAT_WS(',',PlayerNames,NEW.PlayerName) WHERE uid = NEW.PlayerUID;
ELSE
INSERT INTO player_alias (uid, PlayerNames) VALUES (NEW.PlayerUID,NEW.PlayerName);
END IF;
END//
DELIMITER ;