Select ALL columns with join to array and then to JSON

I have code like this in controller:

$results = $this->modelsManager->createBuilder()
            ->columns(array('Car.*','Admin.*'))
            ->from(array('Car'=>'Samochody\Models\Car\Car'))
            ->innerJoin('Samochody\Models\Admin\Admin','Car.admin = Admin.id','Admin')
            ->limit(1)
            ->getQuery()
            ->execute()
            ->toArray();
return $this->response->setJsonContent(array('result' => $results));
```php

But its returning:

{"result":[{"Car":{},"Admin":{}}]}

However if i delete Admin.* i have all fields from Car, but i want js objects with "Car" and "Admin". Any way of doing that ?

I saw somewhere similar problem but i dont remember what was it exactly.