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
				('10', '31', '11', '22', '32', '26', '27')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('10', '31', '11', '22', '32', '26', '27')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=695122.11..695122.12 rows=3 width=20) (actual time=26387.502..26387.503 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=306095 read=21246 written=12
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52779.78..52779.79 rows=1 width=4) (actual time=1509.407..1509.407 rows=1 loops=1)
           Buffers: shared hit=35258 read=1082
           ->  Bitmap Heap Scan on customer  (cost=6603.66..51832.11 rows=379065 width=4) (actual time=316.226..1380.061 rows=380899 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{10,31,11,22,32,26,27}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=35258 read=1082
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6508.89 rows=379065 width=0) (actual time=298.581..298.581 rows=380899 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{10,31,11,22,32,26,27}'::text[]))
                       Buffers: shared hit=12 read=1050
   ->  HashAggregate  (cost=642342.26..642342.30 rows=3 width=20) (actual time=26387.416..26387.416 rows=7 loops=1)
         Buffers: shared hit=306093 read=21246 written=12
         ->  Hash Anti Join  (cost=598393.11..641898.96 rows=59107 width=20) (actual time=24659.032..26332.900 rows=63272 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=306093 read=21246 written=12
               ->  Bitmap Heap Scan on customer  (cost=2898.31..41824.19 rows=138967 width=24) (actual time=1686.868..2834.032 rows=190460 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{10,31,11,22,32,26,27}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=70355 read=1686
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2863.57 rows=138967 width=0) (actual time=1671.553..1671.553 rows=190460 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{10,31,11,22,32,26,27}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35268 read=1618
               ->  Hash  (cost=406494.91..406494.91 rows=15119991 width=4) (actual time=22958.370..22958.370 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=235735 read=19560 written=12
                     ->  Seq Scan on orders  (cost=0.00..406494.91 rows=15119991 width=4) (actual time=0.037..13493.946 rows=15015000 loops=1)
                           Buffers: shared hit=235735 read=19560 written=12
 Total runtime: 26550.939 ms
(30 rows)

COMMIT;
COMMIT