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
				('13', '31', '22', '27', '30', '23', '33')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('13', '31', '22', '27', '30', '23', '33')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=697235.36..697235.37 rows=3 width=20) (actual time=20291.727..20291.728 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=268485 read=59624 dirtied=252
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52973.95..52973.96 rows=1 width=4) (actual time=724.823..724.823 rows=1 loops=1)
           Buffers: shared hit=35287 read=1056
           ->  Bitmap Heap Scan on customer  (cost=6679.56..52016.00 rows=383179 width=4) (actual time=206.915..632.288 rows=381298 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{13,31,22,27,30,23,33}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=35287 read=1056
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6583.76 rows=383179 width=0) (actual time=189.473..189.473 rows=381298 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{13,31,22,27,30,23,33}'::text[]))
                       Buffers: shared hit=9 read=1056
   ->  HashAggregate  (cost=644261.33..644261.38 rows=3 width=20) (actual time=20291.654..20291.654 rows=7 loops=1)
         Buffers: shared hit=268483 read=59624 dirtied=252
         ->  Hash Anti Join  (cost=600208.31..643813.50 rows=59711 width=20) (actual time=19057.022..20245.929 rows=63629 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=268483 read=59624 dirtied=252
               ->  Bitmap Heap Scan on customer  (cost=2943.10..41911.98 rows=140605 width=24) (actual time=826.875..1570.601 rows=190531 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{13,31,22,27,30,23,33}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=35300 read=36750
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2907.95 rows=140605 width=0) (actual time=814.603..814.603 rows=190531 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{13,31,22,27,30,23,33}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35297 read=1593
               ->  Hash  (cost=407703.43..407703.43 rows=15164943 width=4) (actual time=18219.345..18219.345 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=233180 read=22874 dirtied=252
                     ->  Seq Scan on orders  (cost=0.00..407703.43 rows=15164943 width=4) (actual time=0.027..7465.339 rows=15015000 loops=1)
                           Buffers: shared hit=233180 read=22874 dirtied=252
 Total runtime: 20427.441 ms
(30 rows)

COMMIT;
COMMIT