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', '17', '26', '16', '22', '32', '30')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('31', '17', '26', '16', '22', '32', '30')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=694246.67..694246.68 rows=3 width=20) (actual time=16373.509..16373.510 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=257030 read=70079 written=1460
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52964.27..52964.28 rows=1 width=4) (actual time=602.484..602.484 rows=1 loops=1)
           Buffers: shared hit=34227 read=2117
           ->  Bitmap Heap Scan on customer  (cost=6677.49..52006.99 rows=382914 width=4) (actual time=134.547..504.795 rows=381833 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{31,17,26,16,22,32,30}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=34227 read=2117
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6581.77 rows=382914 width=0) (actual time=122.900..122.900 rows=381833 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{31,17,26,16,22,32,30}'::text[]))
                       Buffers: shared hit=12 read=1054
   ->  HashAggregate  (cost=641282.32..641282.36 rows=3 width=20) (actual time=16373.446..16373.450 rows=7 loops=1)
         Buffers: shared hit=257028 read=70079 written=1460
         ->  Hash Anti Join  (cost=597843.92..640835.63 rows=59558 width=20) (actual time=15645.412..16329.607 rows=63564 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=257028 read=70079 written=1460
               ->  Bitmap Heap Scan on customer  (cost=2941.59..41906.48 rows=140453 width=24) (actual time=671.910..928.752 rows=191185 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{31,17,26,16,22,32,30}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=69015 read=3048 written=54
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2906.48 rows=140453 width=0) (actual time=662.707..662.707 rows=191185 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{31,17,26,16,22,32,30}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=34238 read=2655
               ->  Hash  (cost=406090.48..406090.48 rows=15104948 width=4) (actual time=14956.200..14956.200 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=188010 read=67031 written=1406
                     ->  Seq Scan on orders  (cost=0.00..406090.48 rows=15104948 width=4) (actual time=0.018..6189.227 rows=15015000 loops=1)
                           Buffers: shared hit=188010 read=67031 written=1406
 Total runtime: 16475.420 ms
(30 rows)

COMMIT;
COMMIT