Top 5 Spenders in the Galactic Bazaar :Find the Highest-Spending Customers by Total Order Value Advanced

          with customertotals as
  (select c.customerid,
          sum(o.totalamount) as totalspent
   from orders o
   join customers c on o.customerid = c.customerid
   group by c.customerid),
     rankedcustomers as
  (select customerid,
          totalspent,
          rank() over (
                       order by totalspent desc) as rank
   from customertotals)
select customerid,
       totalspent,
       rank
from rankedcustomers
where rank <= 5;