Method getUserIdByCard

public static function getUserIdByCard($card)
{
    $db = Factory::getDBO();
    $query = ' SELECT a.user_id FROM #__phocacart_users AS a' . ' WHERE a.loyalty_card_number = ' . $db->quote($card) . ' AND a.type = 0' . ' LIMIT 1';
    $db->setQuery($query);
    $id = $db->loadResult();
    return $id;
}