$query = new Query();
        $query->sortClauses[] = new Query\SortClause\LocationPriority( Query::SORT_DESC );
        $query->criterion = new Query\Criterion\LogicalAnd(
            array
            (
                new Query\Criterion\ParentLocationId( $parentLocationId ),
                new Query\Criterion\ContentTypeIdentifier( $contentTypeIdentifier ),
            )
        );
        return $searchService->findContent( $query );

SELECT
  `ezcontentobject`.`id`,
  `sort_table_0`.`priority` AS `sort_column_0` 
FROM `ezcontentobject` 
INNER JOIN  ezcontentobject_version ON ezcontentobject.id = ezcontentobject_version.contentobject_id 
LEFT JOIN  `ezcontentobject_tree` AS `sort_table_0` ON `sort_table_0`.`contentobject_id` = `ezcontentobject`.`id` 
LEFT JOIN `ezcontentobject_tree` AS `53a1c75ec0362` ON `53a1c75ec0362`.`contentobject_id` = `ezcontentobject`.`id` 
LEFT JOIN `ezcontentobject_tree` AS `53a1c75ec04be` ON `53a1c75ec04be`.`contentobject_id` = `ezcontentobject`.`id` 
LEFT JOIN `ezcontentobject_tree` AS `53a1c75ec0632` ON `53a1c75ec0632`.`contentobject_id` = `ezcontentobject`.`id` 
LEFT JOIN `ezcontentobject_tree` AS `53a1c75ec08e2` ON `53a1c75ec08e2`.`contentobject_id` = `ezcontentobject`.`id` 
LEFT JOIN `ezcontentobject_tree` AS `53a1c75ec0a1c` ON `53a1c75ec0a1c`.`contentobject_id` = `ezcontentobject`.`id` 
LEFT JOIN `ezcontentobject_tree` AS `53a1c75ec0b76` ON `53a1c75ec0b76`.`contentobject_id` = `ezcontentobject`.`id` 
LEFT JOIN `ezcontentobject_tree` AS `53a1c75ec0cd9` ON `53a1c75ec0cd9`.`contentobject_id` = `ezcontentobject`.`id` 
WHERE
...