Doctrine simple native SQL query

public function findAllDistinctFragments(int $limit)
{
    $sql = "SELECT DISTINCT ON (f.code) * FROM fragment f ORDER BY f.code, f.created_at DESC ";

    $rsm = new ResultSetMappingBuilder($this->getEntityManager());
    $rsm->addRootEntityFromClassMetadata(Fragment::class, 'f');

    $query = $this->getEntityManager()->createNativeQuery($sql, $rsm);

    return $query->getResult();
}