Laravel How to orderby()->first() in eager loading - laravel

Question

I have this query which is working just fine except when i call ->first() function on it, the data from certain relations disappear.
What I am trying to achieve:
I am trying to get the sp_services where price is lowest. The first object (id: 1) in data array has two sp_services, the second object inside data array (id: 13) has only one sp_services. When i do $query->orderBy('sp_services.price', 'DESC')->first(); The object from first one is there but the second one where (id: 6, name: car wash) disappears and there is only empty array.
In the below mentioned JSON I'm only showing the relevant data here. Can anyone please tell me what am i doing wrong here ? and why is it not working. Also is there a better way to achieve desired result.
Query:
$branchesQuery = SpBranch::query();
$branchesQuery->where('status', true);
$branchesQuery->when($request->filled('price'), function($query) use($request) {
return $query->with(['service_provider' => function($query) use($request) {
$query->whereHas('sp_services')
->with(['sp_services' => function($query) use($request) {
$query->orderBy('sp_services.price', 'DESC'); //->first();
}]);
}]);
});
$branches = $branchesQuery->paginate($perPageLimit);
return $branches;
Models:
class SpBranch extends Model
{
public function service_provider()
{
return $this->belongsTo(ServiceProvider::class, 'sp_id');
}
}
class ServiceProvider extends Model
{
public function sp_services()
{
return $this->hasMany(SpService::class, 'sp_id', 'id');
}
}
JSON:
{
"data": [
{
"id": 1,
"sp_id": 1,
"name": "Branch 01",
"status": 1,
"service_provider": {
"id": 1,
"name": "Service Provider 01",
"sp_services": [
{
"id": 3,
"sp_id": 1,
"branch_id": null,
"name": "Service 03",
"price": 50
},
{
"id": 4,
"sp_id": 1,
"branch_id": null,
"name": "Service 04",
"price": 70
}
]
}
},
{
"id": 13,
"sp_id": 5,
"name": "Branch 13",
"status": 1,
"service_provider": {
"id": 5,
"name": "Service Provider 05",
"sp_services": [
{
"id": 6,
"sp_id": 5,
"branch_id": null,
"name": "car wash",
"price": 300
}
]
}
}
]
}

Answer 1

You cannot order or group by a eager loaded table on database, because what WITH method does is that it fires a new query meaning that is not connected to the first one at all, what you can do is you can order or group them in collections meaning after the data is fetch from db you can order them, I think function is called ->sortBy() which will order by the field you want, but it will cost you on performance. If performance is important in your case, you can always use joins to join both tables which will enable you order results directly from database.

Answer 2

class ServiceProvider extends Model
{
public function sp_services()
{
return $this->hasMany(SpService::class, 'sp_id', 'id')->orderBy('price', 'asc');
}
}