with a as( select o.product_id, round(sum(o.quantity*p.unit_price),2) total_sales, p.unit_price, sum(o.quantity) total_quantity, round(sum(o.quantity*p.unit_price)/12,2) avg_monthly_sales from orders o left join products p on o.product_id = p.product_id group by o.product_id,p.unit_price ), b as ( s...