Сайт для формирования петиций

require_once ENGINE_DIR . '/modules/sitelogin.php';

$last_serial_db = $db->query( "SELECT watch FROM " . PREFIX . "_last_serial WHERE news_id='{$_POST['newsid']}' AND users='{$member_id['user_id']}'");
$last_serial_db =  mysqli_fetch_assoc($last_serial_db);
if (empty($last_serial_db)) {
$db->query( "INSERT INTO " . PREFIX . "_last_serial (news_id, users) VALUES('{$_POST['newsid']}', '{$member_id['user_id']}')" );
}
$last_serial_db = $db->query( "SELECT watch FROM " . PREFIX . "_last_serial WHERE news_id='{$_POST['newsid']}' AND users='{$member_id['user_id']}'");
$last_serial_db =  mysqli_fetch_assoc($last_serial_db);
$last_serial_db = unserialize($last_serial_db[watch]);