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
				('10', '17', '21', '12', '23', '15', '29')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('10', '17', '21', '12', '23', '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=694744.02..694744.02 rows=3 width=20) (actual time=20327.961..20327.962 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=265298 read=61816 written=1
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52904.48..52904.49 rows=1 width=4) (actual time=764.959..764.959 rows=1 loops=1)
           Buffers: shared hit=35168 read=1175
           ->  Bitmap Heap Scan on customer  (cost=6645.90..51949.64 rows=381933 width=4) (actual time=165.380..655.133 rows=382285 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{10,17,21,12,23,15,29}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=35168 read=1175
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6550.42 rows=381933 width=0) (actual time=152.450..152.450 rows=382285 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{10,17,21,12,23,15,29}'::text[]))
                       Buffers: shared hit=9 read=1056
   ->  HashAggregate  (cost=641839.46..641839.51 rows=3 width=20) (actual time=20327.881..20327.882 rows=7 loops=1)
         Buffers: shared hit=265296 read=61816 written=1
         ->  Hash Anti Join  (cost=597811.83..641397.04 rows=58989 width=20) (actual time=18779.484..20267.958 rows=63477 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=265296 read=61816 written=1
               ->  Bitmap Heap Scan on customer  (cost=2909.50..41864.02 rows=140058 width=24) (actual time=881.338..1899.358 rows=190885 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{10,17,21,12,23,15,29}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=35180 read=36888
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2874.49 rows=140058 width=0) (actual time=867.358..867.358 rows=190885 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{10,17,21,12,23,15,29}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35178 read=1713
               ->  Hash  (cost=406090.48..406090.48 rows=15104948 width=4) (actual time=17889.145..17889.145 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=230113 read=24928 written=1
                     ->  Seq Scan on orders  (cost=0.00..406090.48 rows=15104948 width=4) (actual time=0.028..7510.396 rows=15015000 loops=1)
                           Buffers: shared hit=230113 read=24928 written=1
 Total runtime: 20494.982 ms
(30 rows)

COMMIT;
COMMIT