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
				('31', '30', '25', '19', '24', '13', '17')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('31', '30', '25', '19', '24', '13', '17')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=698375.75..698375.76 rows=3 width=20) (actual time=13646.613..13646.614 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=268081 read=60566 dirtied=506
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52950.90..52950.91 rows=1 width=4) (actual time=1193.705..1193.705 rows=1 loops=1)
           Buffers: shared hit=12 read=36330
           ->  Bitmap Heap Scan on customer  (cost=6674.67..51994.53 rows=382547 width=4) (actual time=207.139..1085.486 rows=381508 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{31,30,25,19,24,13,17}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=12 read=36330
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6579.04 rows=382547 width=0) (actual time=185.177..185.177 rows=381508 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{31,30,25,19,24,13,17}'::text[]))
                       Buffers: shared hit=9 read=1055
   ->  HashAggregate  (cost=645424.77..645424.82 rows=3 width=20) (actual time=13646.540..13646.542 rows=7 loops=1)
         Buffers: shared hit=268079 read=60566 dirtied=506
         ->  Hash Anti Join  (cost=601386.23..644977.68 rows=59612 width=20) (actual time=13112.282..13611.915 rows=63684 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=268079 read=60566 dirtied=506
               ->  Bitmap Heap Scan on customer  (cost=2940.73..41903.52 rows=140373 width=24) (actual time=1302.454..1500.723 rows=190508 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{31,30,25,19,24,13,17}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=35216 read=36866
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2905.64 rows=140373 width=0) (actual time=1288.545..1288.545 rows=190508 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{31,30,25,19,24,13,17}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=22 read=36866
               ->  Hash  (cost=408509.11..408509.11 rows=15194911 width=4) (actual time=11798.807..11798.807 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=232860 read=23700 dirtied=506
                     ->  Seq Scan on orders  (cost=0.00..408509.11 rows=15194911 width=4) (actual time=0.025..5912.895 rows=15015000 loops=1)
                           Buffers: shared hit=232860 read=23700 dirtied=506
 Total runtime: 13706.561 ms
(30 rows)

COMMIT;
COMMIT