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
				('29', '30', '10', '13', '32', '16', '25')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('29', '30', '10', '13', '32', '16', '25')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=693709.79..693709.80 rows=3 width=20) (actual time=12587.248..12587.249 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=139902 read=186684 written=4
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=53025.64..53025.65 rows=1 width=4) (actual time=846.157..846.157 rows=1 loops=1)
           Buffers: shared hit=10 read=36331
           ->  Bitmap Heap Scan on customer customer_1  (cost=6691.39..52064.22 rows=384565 width=4) (actual time=114.270..774.826 rows=381797 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{29,30,10,13,32,16,25}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35278
                 Buffers: shared hit=10 read=36331
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6595.25 rows=384565 width=0) (actual time=102.991..102.991 rows=381797 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{29,30,10,13,32,16,25}'::text[]))
                       Buffers: shared hit=7 read=1056
   ->  HashAggregate  (cost=640684.07..640684.12 rows=3 width=20) (actual time=12587.186..12587.188 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=139899 read=186684 written=4
         ->  Hash Anti Join  (cost=596665.67..640235.46 rows=59815 width=20) (actual time=11855.452..12562.241 rows=63866 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=139899 read=186684 written=4
               ->  Bitmap Heap Scan on customer  (cost=2945.97..41919.39 rows=140778 width=24) (actual time=908.579..1443.399 rows=190814 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{29,30,10,13,32,16,25}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35158
                     Buffers: shared hit=22 read=72024
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2910.77 rows=140778 width=0) (actual time=899.691..899.691 rows=190814 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{29,30,10,13,32,16,25}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=20 read=36868
               ->  Hash  (cost=405283.20..405283.20 rows=15074920 width=4) (actual time=10788.146..10788.146 rows=15015000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658944kB
                     Buffers: shared hit=139874 read=114660 written=4
                     ->  Seq Scan on orders  (cost=0.00..405283.20 rows=15074920 width=4) (actual time=0.027..4985.318 rows=15015000 loops=1)
                           Buffers: shared hit=139874 read=114660 written=4
 Planning time: 3.176 ms
 Execution time: 12616.354 ms
(34 rows)

COMMIT;
COMMIT