通过关联表在Laravel 5.1中点上按距离排序

public function location()
{
    return $this->hasOne(Location::class);
}

public function user()
{
    return $this->belongsTo(User::class);
}

use Illuminate\Support\Facades\DB;

public function index()
{
    $currentUser = auth()->user();
    $currentLocation = $currentUser->location;

    $users = User::join('locations', 'users.id', '=', 'locations.user_id')
        ->select('users.*', DB::raw('(6371 * acos(cos(radians(' . $currentLocation->latitude . ')) * cos(radians(locations.latitude)) * cos(radians(locations.longitude) - radians(' . $currentLocation->longitude . ')) + sin(radians(' . $currentLocation->latitude . ')) * sin(radians(locations.latitude)))) AS distance'))
        ->orderBy('distance')
        ->get();

    return view('users.index', compact('users'));
}

@foreach($users as $user)
    <div>
        <h2>{{ $user->name }}</h2>
        <p>Distance: {{ $user->distance }} km</p>
    </div>
@endforeach