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', '21', '17', '33', '32', '28', '25')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('19', '21', '17', '33', '32', '28', '25')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=697212.78..697212.78 rows=3 width=20) (actual time=14452.552..14452.553 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=326179 read=1931 dirtied=252
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52957.46..52957.47 rows=1 width=4) (actual time=567.240..567.240 rows=1 loops=1)
           Buffers: shared hit=35285 read=1059
           ->  Bitmap Heap Scan on customer  (cost=6676.03..52000.64 rows=382728 width=4) (actual time=103.252..483.949 rows=382796 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{19,21,17,33,32,28,25}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=35285 read=1059
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6580.35 rows=382728 width=0) (actual time=93.454..93.454 rows=382796 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{19,21,17,33,32,28,25}'::text[]))
                       Buffers: shared hit=7 read=1059
   ->  HashAggregate  (cost=644255.24..644255.28 rows=3 width=20) (actual time=14452.475..14452.478 rows=7 loops=1)
         Buffers: shared hit=326177 read=1931 dirtied=252
         ->  Hash Anti Join  (cost=600206.95..643809.38 rows=59447 width=20) (actual time=13937.385..14429.107 rows=63719 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=326177 read=1931 dirtied=252
               ->  Bitmap Heap Scan on customer  (cost=2941.73..41907.07 rows=140470 width=24) (actual time=632.089..843.572 rows=191074 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{19,21,17,33,32,28,25}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=70455 read=1596
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2906.62 rows=140470 width=0) (actual time=623.092..623.092 rows=191074 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{19,21,17,33,32,28,25}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35295 read=1596
               ->  Hash  (cost=407703.43..407703.43 rows=15164943 width=4) (actual time=13292.428..13292.428 rows=15000000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527344kB
                     Buffers: shared hit=255719 read=335 dirtied=252
                     ->  Seq Scan on orders  (cost=0.00..407703.43 rows=15164943 width=4) (actual time=0.024..4763.099 rows=15000000 loops=1)
                           Buffers: shared hit=255719 read=335 dirtied=252
 Total runtime: 14553.602 ms
(30 rows)

COMMIT;
COMMIT