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
				('23', '14', '11', '30', '13', '26', '19')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('23', '14', '11', '30', '13', '26', '19')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=696314.21..696314.22 rows=3 width=20) (actual time=22339.629..22339.630 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=258044 read=70088 written=117
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52789.66..52789.67 rows=1 width=4) (actual time=1576.935..1576.935 rows=1 loops=1)
           Buffers: shared hit=18 read=36325
           ->  Bitmap Heap Scan on customer  (cost=6605.77..51841.32 rows=379335 width=4) (actual time=151.830..1449.570 rows=381327 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{23,14,11,30,13,26,19}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=18 read=36325
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6510.94 rows=379335 width=0) (actual time=139.452..139.452 rows=381327 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{23,14,11,30,13,26,19}'::text[]))
                       Buffers: shared hit=7 read=1058
   ->  HashAggregate  (cost=643524.48..643524.52 rows=3 width=20) (actual time=22339.549..22339.552 rows=7 loops=1)
         Buffers: shared hit=258042 read=70088 written=117
         ->  Hash Anti Join  (cost=600163.81..643087.57 rows=58255 width=20) (actual time=20562.270..22280.283 rows=63451 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=258042 read=70088 written=117
               ->  Bitmap Heap Scan on customer  (cost=2898.59..41825.16 rows=138993 width=24) (actual time=1746.781..2923.465 rows=190468 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{23,14,11,30,13,26,19}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=5372 read=66701 written=114
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2863.85 rows=138993 width=0) (actual time=1725.427..1725.427 rows=190468 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{23,14,11,30,13,26,19}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=28 read=36861
               ->  Hash  (cost=407703.43..407703.43 rows=15164943 width=4) (actual time=18581.837..18581.837 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=252667 read=3387 written=3
                     ->  Seq Scan on orders  (cost=0.00..407703.43 rows=15164943 width=4) (actual time=0.064..8106.749 rows=15015000 loops=1)
                           Buffers: shared hit=252667 read=3387 written=3
 Total runtime: 22461.627 ms
(30 rows)

COMMIT;
COMMIT