BEGIN;
BEGIN
EXPLAIN (ANALYZE, BUFFERS)
select
	cntrycode,
	count(*) as numcust,
	sum(c_acctbal) as totacctbal
from
	(
		select
			substr(c_phone, 1, 2) as cntrycode,
			c_acctbal
		from
			customer
		where
			substr(c_phone, 1, 2) in
				('12', '13', '20', '33', '30', '25', '34')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('12', '13', '20', '33', '30', '25', '34')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=694094.43..694094.44 rows=3 width=20) (actual time=13838.609..13838.610 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=196016 read=130859 written=11
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52898.70..52898.71 rows=1 width=4) (actual time=1249.083..1249.083 rows=1 loops=1)
           Buffers: shared hit=13 read=36329
           ->  Bitmap Heap Scan on customer customer_1  (cost=6645.53..51944.33 rows=381745 width=4) (actual time=190.578..1136.253 rows=381844 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{12,13,20,33,30,25,34}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35278
                 Buffers: shared hit=13 read=36329
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6550.09 rows=381745 width=0) (actual time=171.667..171.667 rows=381844 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{12,13,20,33,30,25,34}'::text[]))
                       Buffers: shared hit=10 read=1054
   ->  HashAggregate  (cost=641195.66..641195.70 rows=3 width=20) (actual time=13838.524..13838.527 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=196013 read=130859 written=11
         ->  Hash Anti Join  (cost=597219.27..640753.69 rows=58929 width=20) (actual time=13427.457..13817.632 rows=64023 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=196013 read=130859 written=11
               ->  Bitmap Heap Scan on customer  (cost=2909.43..41860.91 rows=139942 width=24) (actual time=1357.836..1588.343 rows=190895 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{12,13,20,33,30,25,34}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35192
                     Buffers: shared hit=35213 read=36869
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2874.44 rows=139942 width=0) (actual time=1342.471..1342.471 rows=190895 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{12,13,20,33,30,25,34}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=22 read=36868
               ->  Hash  (cost=405686.04..405686.04 rows=15089904 width=4) (actual time=11371.973..11371.973 rows=15015000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658944kB
                     Buffers: shared hit=160797 read=93990 written=11
                     ->  Seq Scan on orders  (cost=0.00..405686.04 rows=15089904 width=4) (actual time=0.037..5335.489 rows=15015000 loops=1)
                           Buffers: shared hit=160797 read=93990 written=11
 Planning time: 4.731 ms
 Execution time: 13850.822 ms
(34 rows)

COMMIT;
COMMIT