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
				('24', '25', '19', '26', '17', '15', '29')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('24', '25', '19', '26', '17', '15', '29')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=691684.71..691684.72 rows=3 width=20) (actual time=13539.346..13539.347 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=233545 read=92292
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52884.16..52884.17 rows=1 width=4) (actual time=755.024..755.024 rows=1 loops=1)
           Buffers: shared hit=67 read=36275
           ->  Bitmap Heap Scan on customer customer_1  (cost=6642.44..51930.79 rows=381347 width=4) (actual time=91.295..680.746 rows=382023 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{24,25,19,26,17,15,29}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35278
                 Buffers: shared hit=67 read=36275
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6547.10 rows=381347 width=0) (actual time=82.592..82.592 rows=382023 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{24,25,19,26,17,15,29}'::text[]))
                       Buffers: shared hit=9 read=1055
   ->  HashAggregate  (cost=638800.47..638800.52 rows=3 width=20) (actual time=13539.290..13539.291 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=233542 read=92292
         ->  Hash Anti Join  (cost=594855.19..638355.62 rows=59314 width=20) (actual time=13106.476..13518.679 rows=63475 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=233542 read=92292
               ->  Bitmap Heap Scan on customer  (cost=2905.91..41848.41 rows=139600 width=24) (actual time=818.889..1044.075 rows=190812 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{24,25,19,26,17,15,29}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35168
                     Buffers: shared hit=35244 read=36812
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2871.01 rows=139600 width=0) (actual time=810.161..810.161 rows=190812 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{24,25,19,26,17,15,29}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=77 read=36811
               ->  Hash  (cost=404074.68..404074.68 rows=15029968 width=4) (actual time=11380.991..11380.991 rows=15015000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658944kB
                     Buffers: shared hit=198295 read=55480
                     ->  Seq Scan on orders  (cost=0.00..404074.68 rows=15029968 width=4) (actual time=0.030..4688.380 rows=15015000 loops=1)
                           Buffers: shared hit=198295 read=55480
 Planning time: 2.776 ms
 Execution time: 13569.780 ms
(34 rows)

COMMIT;
COMMIT