Querying Distant Relationships - laravel

Question

I have three tables: users, accounts and hotels. Users and Accounts are connected with belongstoMany relation and Accounts and Hotels are connected the same way. Each User has Accounts and those Accounts have Hotels.
When I have Auth::user(), how I can return all hotels?
$accounts = Auth::user()->accounts()->get();
With the above statement, I can get all Accounts. How can I return all Hotels?
WHAT I TRIED?
public function index(Request $request)
{
$accounts = Auth::user()->accounts()->get();
$hotels = collect();
foreach ($accounts as $key => $a) {
$h = $a->hotels();
$hotels = $hotels->toBase()->merge($h);
}
dd($hotels);
return view('hotels.index',compact('hotels'));
}
but this code dont return me hotels collection which I can use in blade view files

Answer 1

Case 1
In the case you have a relationship as shown in the diagram below
What you are looking for is the hasManyThrough relationship.
From the Laravel documentation
The "has-many-through" relationship provides a convenient shortcut for accessing distant relations via an intermediate relation
In your case, on your User model, you can define the relationship
public function hotels()
{
return $this->hasManyThrough('App\Hotel', 'App\Account');
}
To then get your collection of hotels you can simply use
$hotels = Auth::user()->hotels;
You can also provide extra arguments to the hasManyThrough function to define the keys that are used on each table, great examples of this are given in the documentation linked above!
Case 2
If, instead, you have a relation as shown in the following diagram
It is a little more tricky (or, at least, less clean). The best solution I can think of, that uses the fewest queries is to use with.
$accounts = Auth::user()->accounts()->with('hotels')->get();
Will give you a collection of accounts, each with a hotels child. Now, all we have to do is get the hotels as a standalone collection, this is simple with some neat collection functions provided by Laravel.
$hotels = $accounts->flatMap(function($account) {
return $account->hotels;
})->unique(function ($hotel) {
return $hotel->id;
});
This will do the job of creating a collection of hotels. In my opinion, it would be cleaner and more efficient to simply make a new relationship as shown below.
And then to perform queries, using basic Eloquent methods.