public function getUnitCounts()
{
$dql = 'SELECT SUM(p.stockLevel) AS stockLevel, pu AS partMeasurementUnit FROM ';
$dql .= 'PartKeepr\\PartBundle\\Entity\\PartMeasurementUnit pu LEFT JOIN pu.parts p GROUP BY pu.id';
return $this->entityManager->createQuery($dql)->getArrayResult();
}