Almost Famous: Second Place Products :Identify the Second Best-Selling Product by Category and Total Sales Intermediate

          with producttotals as
  (select p.category,
          p.name as productname,
          sum(od.quantity) as totalsales
   from orderdetails od
   join products p on od.productid = p.productid
   group by p.category,
            p.name)
select category,
       productname,
       totalsales,
       nth_value(productname, 2) over (partition by category
                                       order by totalsales desc) as secondmostpopular
from producttotals;