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
				('19', '18', '21', '29', '27', '20', '22')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('19', '18', '21', '29', '27', '20', '22')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=694164.87..694164.88 rows=3 width=20) (actual time=15999.802..15999.802 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=322417 read=4695 dirtied=254
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52924.38..52924.39 rows=1 width=4) (actual time=704.057..704.057 rows=1 loops=1)
           Buffers: shared hit=35181 read=1163
           ->  Bitmap Heap Scan on customer  (cost=6650.13..51968.18 rows=382478 width=4) (actual time=217.635..606.502 rows=381995 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{19,18,21,29,27,20,22}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=35181 read=1163
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6554.51 rows=382478 width=0) (actual time=199.787..199.787 rows=381995 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{19,18,21,29,27,20,22}'::text[]))
                       Buffers: shared hit=12 read=1054
   ->  HashAggregate  (cost=641240.42..641240.46 rows=3 width=20) (actual time=15999.744..15999.746 rows=7 loops=1)
         Buffers: shared hit=322415 read=4695 dirtied=254
         ->  Hash Anti Join  (cost=597812.76..640799.88 rows=58738 width=20) (actual time=15288.328..15961.630 rows=63783 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=322415 read=4695 dirtied=254
               ->  Bitmap Heap Scan on customer  (cost=2910.43..41867.24 rows=140145 width=24) (actual time=826.917..1091.027 rows=190708 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{19,18,21,29,27,20,22}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=67677 read=4389
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2875.40 rows=140145 width=0) (actual time=806.591..806.591 rows=190708 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{19,18,21,29,27,20,22}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35191 read=1699
               ->  Hash  (cost=406090.48..406090.48 rows=15104948 width=4) (actual time=14452.626..14452.626 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=254735 read=306 dirtied=254
                     ->  Seq Scan on orders  (cost=0.00..406090.48 rows=15104948 width=4) (actual time=0.031..6078.256 rows=15015000 loops=1)
                           Buffers: shared hit=254735 read=306 dirtied=254
 Total runtime: 16120.850 ms
(30 rows)

COMMIT;
COMMIT