A have an error "Trying to get property of non-object" in Laravel

I have code

$room = Room::all();
            $book = DB::table('book_rooms')
                ->whereDate('check_out','>=',$request->check_in)
                ->whereDate('check_in','<=',$request->check_out)
                ->where(function($query){
                    $query->where('status','=',0)
                    ->orWhere('status','=',1);
                })
                ->groupBy('room_id')
                ->get();
                return view('admin.Bookroom.list',['book'=>$book,'room'=>$room]);

So in file list.blade.php show error 'Trying to get property of non-object' Please help me! Thank all

via SpaceLiar