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
				('11', '14', '19', '17', '26', '18', '27')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('11', '14', '19', '17', '26', '18', '27')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=697691.14..697691.14 rows=3 width=20) (actual time=14415.505..14415.507 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=273238 read=55385 written=60
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52912.59..52912.60 rows=1 width=4) (actual time=574.587..574.587 rows=1 loops=1)
           Buffers: shared hit=35285 read=1058 written=52
           ->  Bitmap Heap Scan on customer  (cost=6647.63..51957.20 rows=382155 width=4) (actual time=101.589..477.171 rows=381596 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{11,14,19,17,26,18,27}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=35285 read=1058 written=52
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6552.10 rows=382155 width=0) (actual time=92.173..92.173 rows=381596 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{11,14,19,17,26,18,27}'::text[]))
                       Buffers: shared hit=11 read=1054 written=52
   ->  HashAggregate  (cost=644778.46..644778.51 rows=3 width=20) (actual time=14415.437..14415.441 rows=7 loops=1)
         Buffers: shared hit=273236 read=55385 written=60
         ->  Hash Anti Join  (cost=601356.22..644332.66 rows=59440 width=20) (actual time=13813.856..14381.586 rows=63404 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=273236 read=55385 written=60
               ->  Bitmap Heap Scan on customer  (cost=2910.72..41868.31 rows=140175 width=24) (actual time=648.602..847.788 rows=190415 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{11,14,19,17,26,18,27}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=70406 read=1652 written=52
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2875.68 rows=140175 width=0) (actual time=638.759..638.759 rows=190415 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{11,14,19,17,26,18,27}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35295 read=1592 written=52
               ->  Hash  (cost=408509.11..408509.11 rows=15194911 width=4) (actual time=13152.931..13152.931 rows=15000000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527344kB
                     Buffers: shared hit=202827 read=53733 written=8
                     ->  Seq Scan on orders  (cost=0.00..408509.11 rows=15194911 width=4) (actual time=0.027..5828.382 rows=15000000 loops=1)
                           Buffers: shared hit=202827 read=53733 written=8
 Total runtime: 14527.875 ms
(30 rows)

COMMIT;
COMMIT