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
				('28', '14', '26', '13', '19', '21', '11')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('28', '14', '26', '13', '19', '21', '11')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=695299.48..695299.49 rows=3 width=20) (actual time=17135.562..17135.563 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=194564 read=132800 written=124
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52880.94..52880.95 rows=1 width=4) (actual time=1085.829..1085.830 rows=1 loops=1)
           Buffers: shared hit=9 read=36334
           ->  Bitmap Heap Scan on customer  (cost=6640.91..51927.72 rows=381288 width=4) (actual time=207.715..965.150 rows=381820 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{28,14,26,13,19,21,11}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=9 read=36334
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6545.59 rows=381288 width=0) (actual time=185.173..185.173 rows=381820 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{28,14,26,13,19,21,11}'::text[]))
                       Buffers: shared hit=7 read=1058
   ->  HashAggregate  (cost=642418.46..642418.50 rows=3 width=20) (actual time=17135.482..17135.483 rows=7 loops=1)
         Buffers: shared hit=194562 read=132800 written=124
         ->  Hash Anti Join  (cost=598403.15..641974.28 rows=59224 width=20) (actual time=16391.536..17109.399 rows=63281 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=194562 read=132800 written=124
               ->  Bitmap Heap Scan on customer  (cost=2908.35..41859.83 rows=139942 width=24) (actual time=1189.394..1526.512 rows=190622 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{28,14,26,13,19,21,11}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=20965 read=51099
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2873.37 rows=139942 width=0) (actual time=1176.538..1176.538 rows=190622 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{28,14,26,13,19,21,11}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=19 read=36869
               ->  Hash  (cost=406494.91..406494.91 rows=15119991 width=4) (actual time=15187.872..15187.872 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=173594 read=81701 written=124
                     ->  Seq Scan on orders  (cost=0.00..406494.91 rows=15119991 width=4) (actual time=0.022..6058.292 rows=15015000 loops=1)
                           Buffers: shared hit=173594 read=81701 written=124
 Total runtime: 17271.670 ms
(30 rows)

COMMIT;
COMMIT