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
				('34', '33', '28', '14', '30', '21', '18')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('34', '33', '28', '14', '30', '21', '18')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=694670.20..694670.21 rows=3 width=20) (actual time=23510.367..23510.368 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=184919 read=141937 written=26
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52916.99..52917.00 rows=1 width=4) (actual time=2624.372..2624.373 rows=1 loops=1)
           Buffers: shared hit=10 read=36334
           ->  Bitmap Heap Scan on customer  (cost=6648.56..51961.30 rows=382276 width=4) (actual time=323.951..2498.287 rows=382296 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{34,33,28,14,30,21,18}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=10 read=36334
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6552.99 rows=382276 width=0) (actual time=304.793..304.793 rows=382296 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{34,33,28,14,30,21,18}'::text[]))
                       Buffers: shared hit=8 read=1059
   ->  HashAggregate  (cost=641753.12..641753.17 rows=3 width=20) (actual time=23510.198..23510.200 rows=7 loops=1)
         Buffers: shared hit=184917 read=141937 written=26
         ->  Hash Anti Join  (cost=597220.13..641308.47 rows=59287 width=20) (actual time=22488.752..23457.318 rows=63955 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=184917 read=141937 written=26
               ->  Bitmap Heap Scan on customer  (cost=2910.29..41866.83 rows=140135 width=24) (actual time=2779.784..3272.105 rows=190960 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{34,33,28,14,30,21,18}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=27706 read=44358
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2875.26 rows=140135 width=0) (actual time=2765.226..2765.226 rows=190960 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{34,33,28,14,30,21,18}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=19 read=36873
               ->  Hash  (cost=405686.04..405686.04 rows=15089904 width=4) (actual time=19700.063..19700.063 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=157208 read=97579 written=26
                     ->  Seq Scan on orders  (cost=0.00..405686.04 rows=15089904 width=4) (actual time=0.017..10577.228 rows=15015000 loops=1)
                           Buffers: shared hit=157208 read=97579 written=26
 Total runtime: 23660.883 ms
(30 rows)

COMMIT;
COMMIT