How do you perform inner joins with xPDO

<?php
$categories= array ();
$catTbl= $xpdo->getTableName('Categories');
$catDescTbl= $xpdo->getTableName('CategoriesDescription');
$catColumns= $xpdo->getSelectColumns('Categories', 'cat', 'cat_');
$descColumns= $xpdo->getSelectColumns('CategoriesDescription', 'catdesc', 'catdesc_');
if ($stmt= $xpdo->prepare("SELECT {$catColumns},{$descColumns} FROM {$catTbl} cat JOIN {$catDescTbl} catdesc ON cat.categories_id = catdesc.categories_id AND catdesc.language_id = :language_id AND cat.parent_id = :parent_id")) {
    $stmt->bindParam(':language_id', $language_id, PDO_PARAM_INT);
    $stmt->bindParam(':parent_id', $parent_id, PDO_PARAM_INT);
    if ($stmt->execute()) {
        foreach ($stmt->fetchAll(PDO_FETCH_ASSOC) as $row) {
            $category= $xpdo->newObject('Categories');
            $category->fromArray($row, 'cat_', true);
            $categoryDesc= $xpdo->newObject('CategoriesDescription');
            $categoryDesc->fromArray($row, 'catdesc_', true);
            $category->addMany($categoryDesc);
            $categories[]= $category;
        }
    }
}

$people = array ();
$personTbl = $xpdo->getTableName('Person');
$phoneTbl= $xpdo->getTableName('Phone');
$ppTbl = $xpdo->getTableName('PersonPhone');
$personColumns= $xpdo->getSelectColumns('Person', 'p');
$phoneColumns= $xpdo->getSelectColumns('Phone', 'ph');

if ($stmt= $xpdo->prepare("SELECT $personColumns,$phoneColumns FROM $personTbl AS p, $phoneTbl AS ph, $ppTbl AS pp WHERE p.id=pp.person AND ph.id=pp.phone")) {
    if ($stmt->execute()) {
        foreach ($stmt->fetchAll(PDO_FETCH_ASSOC) as $row) {
            $person= $xpdo->newObject('Person');
            $person->fromArray($row, '', true);
            $phone= $xpdo->newObject('Phone');
            $phone->fromArray($row, '', true);
            $person->addMany($phone);
            $people[]= $person;
        }
    }
}

$table = new MakeTable($xpdo);
$tableData = false;

foreach($people as $person)
{
	$numbers = $person->getMany('Phone');

	foreach ($numbers as $number)
	{
		$tableData[] = array('name' => $person->get('first_name') . ' ' . $person->get('last_name'),
                            'dob' => $person->get('dob'), 'number' => $number->get('number'));
	}
}

return $table->create($tableData);

$personPhone= $person->getMany('PersonPhone');

$personPhone->getOne('Phone');