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
				('17', '14', '18', '22', '24', '23', '13')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('17', '14', '18', '22', '24', '23', '13')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=697795.59..697795.59 rows=3 width=20) (actual time=16229.131..16229.131 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=272928 read=55686 dirtied=497
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52969.44..52969.45 rows=1 width=4) (actual time=1343.507..1343.508 rows=1 loops=1)
           Buffers: shared hit=13 read=36330
           ->  Bitmap Heap Scan on customer  (cost=6678.58..52011.80 rows=383056 width=4) (actual time=156.552..1222.162 rows=381290 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{17,14,18,22,24,23,13}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=13 read=36330
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6582.82 rows=383056 width=0) (actual time=143.506..143.506 rows=381290 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{17,14,18,22,24,23,13}'::text[]))
                       Buffers: shared hit=11 read=1054
   ->  HashAggregate  (cost=644826.07..644826.11 rows=3 width=20) (actual time=16229.053..16229.055 rows=7 loops=1)
         Buffers: shared hit=272926 read=55686 dirtied=497
         ->  Hash Anti Join  (cost=601386.08..644384.86 rows=58827 width=20) (actual time=15648.125..16194.053 rows=63249 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=272926 read=55686 dirtied=497
               ->  Bitmap Heap Scan on customer  (cost=2940.59..41902.96 rows=140357 width=24) (actual time=1491.664..1690.920 rows=190269 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{17,14,18,22,24,23,13}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=35185 read=36864
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2905.50 rows=140357 width=0) (actual time=1468.035..1468.035 rows=190269 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{17,14,18,22,24,23,13}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=25 read=36864
               ->  Hash  (cost=408509.11..408509.11 rows=15194911 width=4) (actual time=14143.200..14143.200 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=237738 read=18822 dirtied=497
                     ->  Seq Scan on orders  (cost=0.00..408509.11 rows=15194911 width=4) (actual time=0.047..6546.812 rows=15015000 loops=1)
                           Buffers: shared hit=237738 read=18822 dirtied=497
 Total runtime: 16343.671 ms
(30 rows)

COMMIT;
COMMIT