Method getUserOrderSum

public static function getUserOrderSum($userId)
{
    $total = 0;
    if ($userId > 0) {
        $db = Factory::getDBO();
        $query = 'SELECT SUM(a.amount) FROM #__phocacart_order_total AS a' . ' LEFT JOIN #__phocacart_orders AS o ON a.order_id = o.id' . ' WHERE o.user_id = ' . (int) $userId . ' AND a.type = ' . $db->quote('brutto');
        $db->setQuery($query);
        $total = $db->loadResult();
        if (!$total) {
            $total = 0;
        }
    }
    return $total;
}