je me suis tromper dans un de mes champs

  $query = 'select * from article order by created desc';
    $result = mysql_query($query, $lien);

    echo 'Vos articles: ';
    echo mysql_num_rows($result);

Bonjour,
j'ai un soucis avec ce code
[php] $query = 'select * from article order by created desc';
$result = mysql_query($query, $lien);

echo 'Vos articles: ';
echo mysql_num_rows($result);[/php]
sa m'affiche une erreur:
[code]Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in C:\apachefriends\xampp\htdocs\assoc\admin\admin_interface.php on line 54[/code]
Merci