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
				('14', '15', '16', '13', '21', '17', '32')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('14', '15', '16', '13', '21', '17', '32')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=694143.12..694143.13 rows=3 width=20) (actual time=20804.302..20804.302 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=237548 read=89297 written=9
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52900.87..52900.88 rows=1 width=4) (actual time=1546.203..1546.203 rows=1 loops=1)
           Buffers: shared hit=14 read=36331
           ->  Bitmap Heap Scan on customer  (cost=6645.14..51946.28 rows=381834 width=4) (actual time=208.693..1425.308 rows=382946 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{14,15,16,13,21,17,32}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=14 read=36331
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6549.68 rows=381834 width=0) (actual time=197.417..197.417 rows=382946 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{14,15,16,13,21,17,32}'::text[]))
                       Buffers: shared hit=12 read=1055
   ->  HashAggregate  (cost=641242.17..641242.22 rows=3 width=20) (actual time=20804.219..20804.221 rows=7 loops=1)
         Buffers: shared hit=237546 read=89297 written=9
         ->  Hash Anti Join  (cost=597219.91..640795.92 rows=59501 width=20) (actual time=19992.824..20755.390 rows=63352 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=237546 read=89297 written=9
               ->  Bitmap Heap Scan on customer  (cost=2910.07..41866.01 rows=140112 width=24) (actual time=1658.604..1970.959 rows=191166 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{14,15,16,13,21,17,32}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=35185 read=36868
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2875.05 rows=140112 width=0) (actual time=1645.558..1645.558 rows=191166 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{14,15,16,13,21,17,32}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=25 read=36867
               ->  Hash  (cost=405686.04..405686.04 rows=15089904 width=4) (actual time=18320.027..18320.027 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=202358 read=52429 written=9
                     ->  Seq Scan on orders  (cost=0.00..405686.04 rows=15089904 width=4) (actual time=0.021..8504.837 rows=15015000 loops=1)
                           Buffers: shared hit=202358 read=52429 written=9
 Total runtime: 20987.590 ms
(30 rows)

COMMIT;
COMMIT