How to get the counts of Student for each Teachers in a single collection by Eloquent

Question

A Teacher has many Students. When I am showing the Teachers list I also want to show the counts of Student for each Teachers. How can I do this by using Eloquent?

I can find the Teachers from this, $teacher= Teacher::where('teacher_status','active')->get();

I can find the Student count from this $student_count = Student::where('teacher_id','teachers.id')->count();

How can I conbine this two query and return the response in a single array/collection?

Answer 1

In your teacher model, create the relationship students:

class Teacher extends Model
{
    public function students()
    {
        return $this->hasMany(Student::class, 'teacher_id');
    }
}

In your controller you can do the following:

public function example(){
    $teachers = Teacher::where('teacher_status','active')->withCount('students')->get();
    
    return view('teacherViewExample', compact('teachers'));
}

In your view (teacherViewExample):

<table>
  <thead>
    <tr>
      <th>Teacher Name</th>
      <th>Students Count</th>
    </tr>
  </thead>
  <tbody>
    @foreach($teachers as $teacher)
    <tr>
      <td>{{ $teacher->name }}</td>
      <td>{{ $teacher->students_count }}</td>
    </tr>
    @endforeach
  </tbody>
</table>

Full documentation on how to use withCount() here: https://laravel.com/docs/9.x/eloquent-relationships#counting-related-models

Sometimes you may want to count the number of related models for a given relationship without actually loading the models. To accomplish this, you may use the withCount method. The withCount method will place a {relation}_count attribute on the resulting models: