BEGIN;
BEGIN
EXPLAIN
select
	o_year,
	sum(case
		when nation = 'ETHIOPIA' then volume
		else 0
	end) / sum(volume) as mkt_share
from
	(
		select
			extract(year from o_orderdate) as o_year,
			l_extendedprice * (1 - l_discount) as volume,
			n2.n_name as nation
		from
			part,
			supplier,
			lineitem,
			orders,
			customer,
			nation n1,
			nation n2,
			region
		where
			p_partkey = l_partkey
			and s_suppkey = l_suppkey
			and l_orderkey = o_orderkey
			and o_custkey = c_custkey
			and c_nationkey = n1.n_nationkey
			and n1.n_regionkey = r_regionkey
			and r_name = 'AFRICA'
			and s_nationkey = n2.n_nationkey
			and o_orderdate between date '1995-01-01' and date '1996-12-31'
			and p_type = 'ECONOMY ANODIZED COPPER'
	) as all_nations
group by
	o_year
order by
	o_year;
                                                                         QUERY PLAN                                                                          
-------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=2229266.48..2229268.30 rows=729 width=38)
   Sort Key: (date_part('year'::text, (orders.o_orderdate)::timestamp without time zone))
   ->  HashAggregate  (cost=2229219.06..2229231.82 rows=729 width=38)
         ->  Nested Loop  (cost=494549.32..2228714.86 rows=25210 width=38)
               ->  Nested Loop  (cost=494549.32..2221524.97 rows=25210 width=16)
                     ->  Hash Join  (cost=494549.32..2214174.11 rows=25243 width=16)
                           Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                           ->  Nested Loop  (cost=0.00..1717286.85 rows=417103 width=16)
                                 ->  Index Only Scan using part_p_type_p_partkey_idx on part  (cost=0.00..48007.43 rows=13893 width=4)
                                       Index Cond: (p_type = 'ECONOMY ANODIZED COPPER'::text)
                                 ->  Index Scan using lineitem_l_partkey_l_quantity_l_shipmode_idx on lineitem  (cost=0.00..119.84 rows=31 width=20)
                                       Index Cond: (l_partkey = part.p_partkey)
                           ->  Hash  (cost=483190.61..483190.61 rows=908697 width=8)
                                 ->  Hash Join  (cost=135391.26..483190.61 rows=908697 width=8)
                                       Hash Cond: (orders.o_custkey = customer.c_custkey)
                                       ->  Bitmap Heap Scan on orders  (cost=96360.64..418034.94 rows=4543487 width=12)
                                             Recheck Cond: ((o_orderdate >= '1995-01-01'::date) AND (o_orderdate <= '1996-12-31'::date))
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..95224.77 rows=4543487 width=0)
                                                   Index Cond: ((o_orderdate >= '1995-01-01'::date) AND (o_orderdate <= '1996-12-31'::date))
                                       ->  Hash  (cost=35280.62..35280.62 rows=300000 width=4)
                                             ->  Nested Loop  (cost=906.17..35280.62 rows=300000 width=4)
                                                   ->  Hash Join  (cost=1.07..2.47 rows=5 width=4)
                                                         Hash Cond: (n1.n_regionkey = region.r_regionkey)
                                                         ->  Seq Scan on nation n1  (cost=0.00..1.25 rows=25 width=8)
                                                         ->  Hash  (cost=1.06..1.06 rows=1 width=4)
                                                               ->  Seq Scan on region  (cost=0.00..1.06 rows=1 width=4)
                                                                     Filter: (r_name = 'AFRICA'::bpchar)
                                                   ->  Bitmap Heap Scan on customer  (cost=905.09..6455.63 rows=60000 width=8)
                                                         Recheck Cond: (c_nationkey = n1.n_nationkey)
                                                         ->  Bitmap Index Scan on customer_c_nationkey_c_custkey_idx  (cost=0.00..890.09 rows=60000 width=0)
                                                               Index Cond: (c_nationkey = n1.n_nationkey)
                     ->  Index Scan using pk_supplier on supplier  (cost=0.00..0.28 rows=1 width=8)
                           Index Cond: (s_suppkey = lineitem.l_suppkey)
               ->  Index Scan using pk_nation on nation n2  (cost=0.00..0.27 rows=1 width=30)
                     Index Cond: (n_nationkey = supplier.s_nationkey)
(35 rows)

COMMIT;
COMMIT