Relative Product Popularity :Evaluate Product Sales Performance Within Each Category by Relative Popularity and Rank Percentage Intermediate

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