no, così:

codice:
$rq = "SELECT * FROM #__autoexp_add LEFT JOIN #__users ON #__autoexp_add.user_id=#__users.id WHERE user_id='$car1->user_id'";
		$database->setQuery($rq);
		$cars_data2 = $database->loadObjectList();
		$nome_con_xml = $cars_data2[0]->username;