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
				('15', '14', '10', '24', '13', '22', '32')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('15', '14', '10', '24', '13', '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=699902.26..699902.27 rows=3 width=20) (actual time=20931.476..20931.476 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=326635 read=2494 dirtied=253 written=331
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52869.50..52869.51 rows=1 width=4) (actual time=1089.894..1089.895 rows=1 loops=1)
           Buffers: shared hit=34966 read=1376 written=219
           ->  Bitmap Heap Scan on customer  (cost=6638.47..51917.06 rows=380975 width=4) (actual time=255.344..966.614 rows=381598 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{15,14,10,24,13,22,32}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=34966 read=1376 written=219
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6543.22 rows=380975 width=0) (actual time=233.358..233.358 rows=381598 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{15,14,10,24,13,22,32}'::text[]))
                       Buffers: shared hit=13 read=1051 written=142
   ->  HashAggregate  (cost=647032.68..647032.73 rows=3 width=20) (actual time=20931.393..20931.396 rows=7 loops=1)
         Buffers: shared hit=326633 read=2494 dirtied=253 written=331
         ->  Hash Anti Join  (cost=602531.19..646589.55 rows=59085 width=20) (actual time=19424.045..20876.230 rows=63205 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=326633 read=2494 dirtied=253 written=331
               ->  Bitmap Heap Scan on customer  (cost=2905.41..41849.43 rows=139658 width=24) (actual time=1216.234..2190.198 rows=190485 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{15,14,10,24,13,22,32}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=70125 read=1933 written=331
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2870.50 rows=139658 width=0) (actual time=1194.982..1194.982 rows=190485 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{15,14,10,24,13,22,32}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=34978 read=1910 written=330
               ->  Hash  (cost=409314.79..409314.79 rows=15224879 width=4) (actual time=17944.443..17944.443 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=256505 read=561 dirtied=253
                     ->  Seq Scan on orders  (cost=0.00..409314.79 rows=15224879 width=4) (actual time=0.063..9094.584 rows=15015000 loops=1)
                           Buffers: shared hit=256505 read=561 dirtied=253
 Total runtime: 21062.259 ms
(30 rows)

COMMIT;
COMMIT