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
				('30', '28', '19', '26', '15', '22', '32')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('30', '28', '19', '26', '15', '22', '32')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=693461.18..693461.18 rows=3 width=20) (actual time=19280.488..19280.488 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=284784 read=42067 written=9
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52858.49..52858.50 rows=1 width=4) (actual time=1158.956..1158.956 rows=1 loops=1)
           Buffers: shared hit=35284 read=1061
           ->  Bitmap Heap Scan on customer  (cost=6636.13..51906.80 rows=380673 width=4) (actual time=207.374..1019.153 rows=382227 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{30,28,19,26,15,22,32}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=35284 read=1061
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6540.97 rows=380673 width=0) (actual time=192.828..192.828 rows=382227 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{30,28,19,26,15,22,32}'::text[]))
                       Buffers: shared hit=6 read=1061
   ->  HashAggregate  (cost=640602.61..640602.66 rows=3 width=20) (actual time=19280.411..19280.414 rows=7 loops=1)
         Buffers: shared hit=284782 read=42067 written=9
         ->  Hash Anti Join  (cost=597213.46..640164.15 rows=58461 width=20) (actual time=17819.821..19221.613 rows=63551 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=284782 read=42067 written=9
               ->  Bitmap Heap Scan on customer  (cost=2903.62..41843.05 rows=139483 width=24) (actual time=1299.789..2214.136 rows=191134 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{30,28,19,26,15,22,32}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=52001 read=20058
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2868.75 rows=139483 width=0) (actual time=1284.142..1284.142 rows=191134 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{30,28,19,26,15,22,32}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35293 read=1599
               ->  Hash  (cost=405686.04..405686.04 rows=15089904 width=4) (actual time=16507.716..16507.716 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=232778 read=22009 written=9
                     ->  Seq Scan on orders  (cost=0.00..405686.04 rows=15089904 width=4) (actual time=0.100..8136.931 rows=15015000 loops=1)
                           Buffers: shared hit=232778 read=22009 written=9
 Total runtime: 19405.281 ms
(30 rows)

COMMIT;
COMMIT