<?php
require_once('system/incfiles/mysqli_connect.php');
$q = $db->query('SELECT `benzin`, `bak`, `id` FROM `user`');
while($post = $q->fetch_array()){
if($post['benzin'] < $post['bak']) $db->query("UPDATE `user` SET `benzin` = `benzin` + 1 WHERE `id` ='$post[id]'");
}
?>