BEGIN;
BEGIN
EXPLAIN
select
	o_year,
	sum(case
		when nation = 'ALGERIA' 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 = 'SMALL BURNISHED NICKEL'
	) as all_nations
group by
	o_year
order by
	o_year;
                                                                        QUERY PLAN                                                                         
-----------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=1772488.32..1772490.15 rows=732 width=38)
   Sort Key: (date_part('year'::text, (orders.o_orderdate)::timestamp without time zone))
   ->  HashAggregate  (cost=1772440.68..1772453.49 rows=732 width=38)
         Group Key: date_part('year'::text, (orders.o_orderdate)::timestamp without time zone)
         ->  Hash Join  (cost=39460.35..1771939.40 rows=25064 width=38)
               Hash Cond: (supplier.s_nationkey = n2.n_nationkey)
               ->  Nested Loop  (cost=39458.79..1771467.89 rows=25064 width=16)
                     ->  Hash Join  (cost=39458.50..1763378.07 rows=25072 width=16)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           ->  Nested Loop  (cost=427.81..1723626.55 rows=125362 width=20)
                                 ->  Nested Loop  (cost=427.38..1521836.15 rows=412125 width=16)
                                       ->  Bitmap Heap Scan on part  (cost=426.81..28599.46 rows=13727 width=4)
                                             Recheck Cond: ((p_type)::text = 'SMALL BURNISHED NICKEL'::text)
                                             ->  Bitmap Index Scan on part_p_type_p_partkey_idx  (cost=0.00..423.38 rows=13727 width=0)
                                                   Index Cond: ((p_type)::text = 'SMALL BURNISHED NICKEL'::text)
                                       ->  Index Scan using lineitem_l_partkey_l_quantity_l_shipmode_idx on lineitem  (cost=0.56..108.47 rows=31 width=20)
                                             Index Cond: (l_partkey = part.p_partkey)
                                 ->  Index Scan using pk_orders on orders  (cost=0.43..0.48 rows=1 width=12)
                                       Index Cond: (o_orderkey = lineitem.l_orderkey)
                                       Filter: ((o_orderdate >= '1995-01-01'::date) AND (o_orderdate <= '1996-12-31'::date))
                           ->  Hash  (cost=35280.69..35280.69 rows=300000 width=4)
                                 ->  Nested Loop  (cost=906.18..35280.69 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=905.11..6455.64 rows=60000 width=8)
                                             Recheck Cond: (c_nationkey = n1.n_nationkey)
                                             ->  Bitmap Index Scan on customer_c_nationkey_c_custkey_idx  (cost=0.00..890.11 rows=60000 width=0)
                                                   Index Cond: (c_nationkey = n1.n_nationkey)
                     ->  Index Scan using pk_supplier on supplier  (cost=0.29..0.31 rows=1 width=8)
                           Index Cond: (s_suppkey = lineitem.l_suppkey)
               ->  Hash  (cost=1.25..1.25 rows=25 width=30)
                     ->  Seq Scan on nation n2  (cost=0.00..1.25 rows=25 width=30)
 Planning time: 9.849 ms
(37 rows)

COMMIT;
COMMIT