Как вывести родителей ресурса (категории товаров)?

<?php
if (empty($rid)) {$rid = $modx->resource->id;}
if (empty($pid)) {$pid = $modx->resource->parent;}
if (empty($delimeter)) {$delimeter = ' , ';}
$scheme = $modx->getOption('link_tag_scheme', null, 'full', true);

$q = $modx->newQuery('msCategory');
$q->leftJoin('msCategoryMember', 'msCategoryMember', array(
    '`msCategory`.`id` = `msCategoryMember`.`category_id`'
));
$q->sortby('pagetitle','ASC');
$q->groupby('id');
$q->select(array('id','pagetitle'));
$q->where('`msCategoryMember`.`product_id` = '.$rid.' OR `id` = '.$pid);

$result = array();
if ($q->prepare() && $q->stmt->execute()) {
    while ($row = $q->stmt->fetch(PDO::FETCH_ASSOC)) {
        $url = $modx->makeUrl($row['id'], '', '', $scheme);
        $result[] = '<a href="'.$url.'">'.$row['pagetitle'].'</a>';
    }
}
return implode($delimeter, $result);