Species Spending, Shift by Shift :Compare Consecutive Customer Order Totals Within Each Species Group Intermediate

          with customer_orders as
  (select o.customerid,
          c.species,
          o.orderdate,
          o.totalamount
   from orders o
   join customers c on o.customerid = c.customerid)
select customerid,
       species,
       orderdate,
       totalamount,
       lead(totalamount) over (partition by species
                               order by orderdate) as next_species_order_amount
from customer_orders;