MODX Revolution newQuery groupby & SUM

groupby_sum.php

<?php
// ********************************* //
/** @var mindbox $mindbox */
$modx->loadClass('modMindbox', MODX_CORE_PATH . 'components/mindbox/model/', true, true);
$mindbox = new modMindbox($modx, []);
if (!$mindbox) {
    return 'Could not load modMindbox class!';
}

$q = $modx->newQuery('msOrder', [
    'id:>=' => 42446,
]);
$total = $modx->getCount('msOrder', $q);
$q->sortby('id', 'ASC');
$q->select('num, user_id, SUM(cost) as total_spent');
$q->groupby('user_id');

if ($q->prepare() && $q->stmt->execute()) {
    while ($row = $q->stmt->fetch(PDO::FETCH_ASSOC)) {
        if ($row['total_spent'] > 0) {
            $percent = $mindbox->getCustomerSegmentation($row['user_id']);
            usleep(50000);
            $percent = $percent > 0 ? $percent : 3;
            $bonuses = $row['total_spent'] / 100 * $percent;
            print $row['user_id'] . " - " . $row['total_spent'] . " - $percent <br>";
            if ($bonuses > 0) {
                print $bonuses.'<br>';
                // $mindbox->changeBalance($row['user_id'], $bonuses);
                usleep(250000);
            }
        }
    }
}