$data = DB::table("items")
  ->select("items.*","items_count.price_group","items_count.quantity_group")
  ->join(DB::raw("(SELECT 
      items_count.id_item,
      GROUP_CONCAT(items_count.price) as price_group,
      GROUP_CONCAT(items_count.quantity) as quantity_group
      FROM items_count
      GROUP BY items_count.id_item
      ) as items_count"),function($join){
        $join->on("items_count.id_item","=","items.id");
  })
  ->groupBy("items.id")
  ->get();
print_r($data);