$qb = $this->createQueryBuilder('u');
$qb->leftJoin('u.admin', 'admin')
->Select($qb->expr()->count('admin'))
->addSelect('admin.username')
->addGroupBy('admin.username');

array(1) { [0]=>  array(2) {    [1]=>
int(1)
["username"]=>
string(5) "admin"  }}

$e = $this->getDoctrine()->getRepository(User::class);
    $qb = $e->createQueryBuilder('u')
        ->join('u.statictics', 's')
        ->select('COUNT(s.id) as sCnt')
        ->addSelect('u.username')
        ->addGroupBy('u.username')
    ;