Method getAmountOfOrders

public function getAmountOfOrders($numberOfDate = -1, $dateFrom = '', $dateTo = '')
{
    if ($numberOfDate == -1) {
        $numberOfDate = 7;
    }
    if ($dateFrom == '') {
        $dateFrom = PhocacartDate::getCurrentDate($numberOfDate);
    }
    if ($dateTo == '') {
        $dateTo = PhocacartDate::getCurrentDate();
    }
    $db = Factory::getDbo();
    $q = ' SELECT SUM(t.amount) FROM #__phocacart_orders AS a';
    $q .= ' LEFT JOIN #__phocacart_order_total AS t ON a.id = t.order_id';
    $q .= ' WHERE a.published = 1';
    $q .= ' AND t.type = ' . $db->quote('brutto');
    $q .= ' AND DATE(a.date) >= ' . $db->quote($dateFrom) . ' AND DATE(a.date) <= ' . $db->quote($dateTo);
    $whereOrderStatus = '';
    if (!PhocacartStatistics::setWhereByOrderStatus($whereOrderStatus)) {
        return 0;
    }
    if ($whereOrderStatus != '') {
        $q .= 'AND ' . $whereOrderStatus;
    }
    $db->setQuery($q);
    $count = $db->loadRow();
    if (isset($count[0]) && (int) $count[0] != 0) {
        return $this->abreviateNumbers($count[0]);
    }
    return 0;
}