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', '33', '26', '21', '15', '12', '24')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('17', '33', '26', '21', '15', '12', '24')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=698818.06..698818.07 rows=3 width=20) (actual time=21895.345..21895.346 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=227931 read=101209
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52882.73..52882.74 rows=1 width=4) (actual time=1594.300..1594.300 rows=1 loops=1)
           Buffers: shared hit=9 read=36335
           ->  Bitmap Heap Scan on customer  (cost=6641.29..51929.38 rows=381337 width=4) (actual time=211.459..1470.539 rows=382353 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{17,33,26,21,15,12,24}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=9 read=36335
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6545.95 rows=381337 width=0) (actual time=190.867..190.867 rows=382353 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{17,33,26,21,15,12,24}'::text[]))
                       Buffers: shared hit=6 read=1060
   ->  HashAggregate  (cost=645935.25..645935.30 rows=3 width=20) (actual time=21895.251..21895.253 rows=7 loops=1)
         Buffers: shared hit=227929 read=101209
         ->  Hash Anti Join  (cost=602531.91..645496.03 rows=58563 width=20) (actual time=20562.157..21841.320 rows=63389 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=227929 read=101209
               ->  Bitmap Heap Scan on customer  (cost=2906.13..41851.96 rows=139727 width=24) (actual time=1734.569..2529.460 rows=190999 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{17,33,26,21,15,12,24}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=20 read=72049
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2871.20 rows=139727 width=0) (actual time=1708.531..1708.531 rows=190999 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{17,33,26,21,15,12,24}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=18 read=36874
               ->  Hash  (cost=409314.79..409314.79 rows=15224879 width=4) (actual time=18810.101..18810.101 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=227906 read=29160
                     ->  Seq Scan on orders  (cost=0.00..409314.79 rows=15224879 width=4) (actual time=0.044..6606.547 rows=15015000 loops=1)
                           Buffers: shared hit=227906 read=29160
 Total runtime: 22107.860 ms
(30 rows)

COMMIT;
COMMIT