url: jdbc:mysql://92.222.71.96:3306/forumdb?autoReconnect=true&useUnicode=true&characterEncoding=UTF-8

PreparedStatement ps = conn.prepareStatement("SELECT `money` FROM `st_users` WHERE `username`=?");

ps = conn.prepareStatement("UPDATE `st_users` SET `money`=`money`-? WHERE `username`=?");