The Final Product per Category :Find the Most Recently Sold Product and Its Sale Date by Category Intermediate

          select distinct p.category,
                last_value(p.name) over (partition by p.category
                                         order by o.orderdate rows between unbounded preceding and unbounded following) as productname,
                                        last_value(o.orderdate::date) over (partition by p.category
                                                                            order by o.orderdate rows between unbounded preceding and unbounded following) as lastsolddate
from orderdetails od
join orders o on od.orderid = o.orderid
join products p on od.productid = p.productid
order by p.category;