Laravel do one query

The problem is that you need to load the views relation before using it in the foreach. You can use withCount with your example:

$posts = App\Post::withCount('views')->get();

foreach ($posts as $post) {
    echo $post->views_count;
}

Docs: https://laravel.com/docs/5.7/eloquent-relationships#counting-related-models

@MANELGAVALDA - But appends is not loading default views attribute? Why?

@DRONAX - You can use the withCount method above or if you want to use your method:

When you are doing this:

$this->views()->count()

You are using the query builder to count your views() relation: If you want to use your accesor without doing the 100 queries you need to load the relation before using it, and using the collection count:

protected $appends = ['views'];

public function getViewsAttribute()
{
    return $this->views->count(); //removed the () in views so you are working with collections instead. 
}

Then your $posts variable query needs to eager load your views relation:

$posts = App\Post::with('views')->get();

And you will end up with one query using your method.

You are not using the views attribute, you are calling the views relationship.

return $this->views()->count();

performs a query every time it is called

return $this->views->count();

does not.

But the solution by @manelgavalda is better

Also, you should look up what the $appends property does as it is not eager loading.