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
				('22', '13', '15', '18', '32', '30', '19')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('22', '13', '15', '18', '32', '30', '19')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=693449.07..693449.08 rows=3 width=20) (actual time=29141.170..29141.170 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=280867 read=45744
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52847.24..52847.25 rows=1 width=4) (actual time=3932.263..3932.263 rows=1 loops=1)
           Buffers: shared hit=11 read=36335
           ->  Bitmap Heap Scan on customer  (cost=6633.75..51896.33 rows=380365 width=4) (actual time=282.396..3795.466 rows=382476 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{22,13,15,18,32,30,19}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=11 read=36335
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6538.66 rows=380365 width=0) (actual time=271.069..271.069 rows=382476 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{22,13,15,18,32,30,19}'::text[]))
                       Buffers: shared hit=8 read=1060
   ->  HashAggregate  (cost=640601.75..640601.79 rows=3 width=20) (actual time=29141.061..29141.066 rows=7 loops=1)
         Buffers: shared hit=280865 read=45744
         ->  Hash Anti Join  (cost=596622.89..640156.93 rows=59309 width=20) (actual time=27633.014..29084.457 rows=63745 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=280865 read=45744
               ->  Bitmap Heap Scan on customer  (cost=2903.19..41841.57 rows=139443 width=24) (actual time=4064.164..5049.944 rows=190891 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{22,13,15,18,32,30,19}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=35196 read=36876
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2868.33 rows=139443 width=0) (actual time=4050.879..4050.879 rows=190891 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{22,13,15,18,32,30,19}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=20 read=36873
               ->  Hash  (cost=405283.20..405283.20 rows=15074920 width=4) (actual time=23559.497..23559.497 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=245666 read=8868
                     ->  Seq Scan on orders  (cost=0.00..405283.20 rows=15074920 width=4) (actual time=0.038..13379.919 rows=15015000 loops=1)
                           Buffers: shared hit=245666 read=8868
 Total runtime: 29312.290 ms
(30 rows)

COMMIT;
COMMIT