How to get SUM () of the product of 2 fields in one line?

Question

Laravel

Like
$sum = \App\OnlineGood::where('order_id', $id)->sum();
and sum price*quantity

Answer 1

$sum = \App\OnlineGood::where('order_id', $id)->sum(DB::raw('price*quantity'));

Answer 2

Try sum(DB::raw("price*quantity"))