Model

User.php

class User extends Authenticatable
{
   
    public function roles()
    {
        return $this->belongsToMany(Role::class, 'role_user');
    }
}

Role.php

       
class Role extends Model
{
    /**
     * The users that belong to the role.
     */
    public function users()
    {
        return $this->belongsToMany(User::class, 'role_user');
    }
}

Retrive the records

$user = User::find(1); dd($user->roles);
$role = Role::find(1); dd($role->users);

Create the records

$user = User::find(2); $roleIds = [1, 2];$user->roles()->attach($roleIds);

$user = User::find(3); $roleIds = [1, 2];$user->roles()->sync($roleIds);


$role = Role::find(1); $userIds = [10, 11];$role->users()->attach($userIds);


$role = Role::find(2); $userIds = [10, 11];$role->users()->sync($userIds);

OR

in Models/Student.php

  public function subject()
    {
        return $this->belongstoMany('App\Models\Subject');
    }
  

in Models/Subject.php

  public function student()
    {
        return $this->belongstoMany('App\Models\Student');
    }
  

Get data

  $student = Student::find(1);
        dd($student->subject);
  

Students who have subjects

  $student = Student::has('subject')->get();
        dd($student);
  

Students who does not have subjects

  public function index(){
        $student = Student::doesntHave('subject')->get();
        dd($student);
    }
  

Students which have a particular subject

  public function index(){
        $student = Subject::with('student')->where('id',2)->get();
        dd($student);
    }
  

Fetch count of subjects each student has

  $student = Student::withCount('subject')->get();
        dd($student);
  

Fetch count of subjects each student has order by subject_count in descending order

  $student = Student::withCount('subject')->orderBy('subject_count','desc')->get();
        dd($student);
  

Fetch students with 2 or more subjects

  $student = Student::has('subject','>=',2)->get();
        dd($student);
  

Fetch students with grade >= 90 , we will use grade in Pivot Table

  $student = Student::with('subject')
        ->whereHas('subject', function($query){
            $query->where('grade','>=',90);
        })->get();
        dd($student);