Laravel 5.2关系返回空数组

Question

I have two models and need to pull both and filter the results based on some conditions

Mobile: id, name, make ...

Offer: id, modelid, retailerid...

my Models are set up like this:

// Mobile
public function offer()
{
    return $this->hasMany('App/Offer','modelid','id');
}


// Offer
public function mobile()
{
    return $this->belongsTo('App/Mobile','modelid');
}

when I run

 $offers = App\Mobile::with(['offer'=>function($q){
     $q->orderBy('phonecost','asc')->first();
 }])->orderBy('Popularity','desc')->paginate(10);

I get an empty array in the offer relationship