Laravel Dashboard Query on Enrolled students this Year?

For example, I have five tables (School, Student, Class, Session, and Enrollment) the Enrollment Table store the Primary Key of other tables, Now I like to count in Session wise that how Many students have enrolled in Session 2019-2020 and display in the dashboard.

 public function index()

    {
        
            $schools=School::all();
            $students=Student::all();
            $sessions=Session::all();
            $enrollements=Enrollement::all();
        
        return view('dashboard',compact('schools','students','enrollements','sessions'));
    }

1. when I write {{$sessions->latest()}} it show the following error """Method Illuminate\Database\Eloquent\Collection::latest does not exist""
2. and how to pass session year (String) to enrollement to count?

could anyone suggest the best method to solve the following problem?

1. For collections , use last() method ($sessions->last()) https://laravel.com/docs/7.x/collections#method-last

2. I don't know how your table is structured, but you need to group by year and then compare

   $enrollementsByYear = Enrollment::selectRaw('year, count(year) AS enrollmentsByYear')
                                   ->groupBy('year')
                                   ->get();
   

Then in $enrollementsByYear you will have a collection where you can compare the year of the session and mount your table. Change year with the actual column name.

You can easily compare with something like:

@foreach ($sessions as $session)
    @foreach ($enrollementsByYear as $y)
        @if ($session->year == $y->year)
            <label>{{ $session->year }}</label>: <span> {{$y->enrollmentsByYear }}</span>
        @endif
    @endforeach
@endforeach