select
	supp_nation,
	cust_nation,
	l_year,
	sum(volume) as revenue
from
	(
		select
			n1.n_name as supp_nation,
			n2.n_name as cust_nation,
			substr(l_shipdate, 1, 4) as l_year, -- modified not to include date_part('year', l_shipdate)
			l_extendedprice * (1 - l_discount) as volume
		from
			supplier,
			lineitem,
			orders,
			customer,
			nation n1,
			nation n2
		where
			s_suppkey = l_suppkey
			and o_orderkey = l_orderkey
			and c_custkey = o_custkey
			and s_nationkey = n1.n_nationkey
			and c_nationkey = n2.n_nationkey
			and (
				(n1.n_name = 'ROMANIA' and n2.n_name = 'INDIA')
				or (n1.n_name = 'INDIA' and n2.n_name = 'ROMANIA')
			)
			and l_shipdate between 
			cast('1995-01-01' as datetime) and cast('1996-12-31' as datetime)
	) as shipping
group by
	supp_nation,
	cust_nation,
	l_year
order by
	supp_nation,
	cust_nation,
	l_year;
