EXPLAIN ANALYZE


select
	n_name,
		sum(l_extendedprice * (1 - l_discount)) as revenue
		from
			customer,
				orders,
					lineitem,
						supplier,
							nation,
								region
								where
									c_custkey = o_custkey
										and l_orderkey = o_orderkey
											and l_suppkey = s_suppkey
												and c_nationkey = s_nationkey
													and s_nationkey = n_nationkey
														and n_regionkey = r_regionkey
															and r_name = 'AFRICA'
																and o_orderdate >= date '1994-01-01'
																	and o_orderdate < date '1994-01-01' + interval '1' year
																	group by
																		n_name
																		order by
																			revenue desc;