Laravel Eloquent: How to order results of related models? - php

Question

I have a model called School and it has many Students .
Here is the code in my model:
public function students()
{
return $this->hasMany('Student');
}
I am getting all the students with this code in my controller:
$school = School::find($schoolId);
and in the view:
#foreach ($school->students as $student)
Now I want to order the Students by some field in the students table. How can I do that?

Answer 1

You have a few ways of achieving this:
// when eager loading
$school = School::with(['students' => function ($q) {
$q->orderBy('whateverField', 'asc/desc');
}])->find($schoolId);
// when lazy loading
$school = School::find($schoolId);
$school->load(['students' => function ($q) {
$q->orderBy('whateverField', 'asc/desc');
}]);
// or on the collection
$school = School::find($schoolId);
// asc
$school->students->sortBy('whateverProperty');
// desc
$school->students->sortByDesc('whateverProperty');
// or querying students directly
$students = Student::whereHas('school', function ($q) use ($schoolId) {
$q->where('id', $schoolId);
})->orderBy('whateverField')->get();

Answer 2

you can add orderBy to your relation, so the only thing you need to change is
public function students()
{
return $this->hasMany('Student');
}
to
public function students()
{
return $this->hasMany('Student')->orderBy('id', 'desc');
}

Answer 3

To answer the original question, the students dynamic property can also be accessed as a relationship method.
So you have this to fetch all students:
$students = $school->students;
Now as a relationship method, this is equivalent:
$students = $school->students()->get();
Given this, you can now add in some ordering:
$students = $school->students()->orderBy('students.last_name')->get();
Since eloquent will be performing a join, make sure to include the table name when referencing the column to order by.
You can also add this to your students method if you want to set a default order that $school->students will always return. Check out the documentation for hasMany() to see how this works.

Answer 4

For Many to one relation I found one answer on:
https://laracasts.com/discuss/channels/eloquent/order-by-on-relationship
$order = 'desc';
$users = User::join('roles', 'users.role_id', '=', 'roles.id')
->orderBy('roles.label', $order)
->select('users.*')
->paginate(10);
this can save day... of anyone

Answer 5

You can use this like this:
$students = $school->students()->orderBy('id', 'desc');
You can also use
$students = $school->students()->orderBy('id', 'desc')->paginate(10);