App\Models\Store\Order::itemsQuantities PHP Method

    public static function itemsQuantities($orders)
    {
        $query = clone $orders;
        $query->join('order_items', 'orders.order_id', '=', 'order_items.order_id')->join('products', 'order_items.product_id', '=', 'products.product_id')->groupBy('order_items.product_id')->groupBy('name')->select(DB::raw('sum(order_items.quantity) as quantity, name, products.product_id'));
        return $query->get();
    }

 public function show($id = null)
 {
     $orders = Store\Order::with('user', 'address', 'address.country', 'items.product');
     if ($id) {
         $orders->where('orders.order_id', $id);
     } else {
         $orders->where('orders.status', 'paid');
     }
     $ordersItemsQuantities = Store\Order::itemsQuantities($orders);
     $orders = $orders->orderBy('created_at')->get();
     return view('store.admin', compact('orders', 'ordersItemsQuantities'));
 }