tested on SQL 7.0

select products.productname, isnull(sums.totalquantity, 0), isnull(sums.extendedprice, 0)
from products left outer join
(
select productid, sum(quantity) as TotalQuantity,
sum(quantity * unit_price*(1-discount)) as ExtendedPrice
from order_details
group by productid
) sums
on products.productid=sums.productid
order by extendedprice desc

If you don't care about products that haven't sold, you can drop the isnulls and do an inner join.