Laravel - Get records from one table that doesn't exist in another with a where clause attached

$current_academic = Academic::where('status', 1)->first();

$students = \DB::table('students')
    ->select(
        'students.id',
        'first_name'
    )
    ->whereNotExists( function ($query) use ($current_academic) {
        $query->select(DB::raw(1))
        ->from('enrollments')
        ->whereRaw('students.id = enrollments.student_id')
        ->where('enrollments.academic_id', '=', $current_academic->id);
    })
    ->get();

Let's give some details:

1- whereNotExists clause will return only students that doesn't have any row in the sub query.

2- the sub query select students that exists in enrollments table and their academics_id is 10

Hope this helps

$students = \DB::table('students')
        ->select(
            'students.id',
            'first_name'
        )
        ->leftJoin('enrollments','enrollments.student_id','=','students.id')
        ->whereNull('enrollments.student_id')
        ->orWhere('enrollments.academic_id','<>',$current_academic->id)
        ->get();

Let's do this the most eloquential way possible:

First off, you need to have this in your Student.php model file

public function academics()
{
    return $this->belongsToMany('App\Academic', 'enrollments', 'student_id', 'academic_id'); 
}

and this in your Academic.php model file

public function students()
{
    return $this->belongsToMany('App\Student', 'enrollments', 'academic_id','student_id'); 
}

now you can get what you want this way:

$students = \App\Student::whereDoesntHave('academics')
->orWhereHas('academics',function($q) use ($academic){
  $q->where('id',$academic->id)->count();
},'=',0)->get();