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
				('22', '23', '28', '17', '24', '19', '21')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('22', '23', '28', '17', '24', '19', '21')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=693590.39..693590.40 rows=3 width=20) (actual time=17066.740..17066.741 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=322530 read=4073 written=3
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52921.20..52921.21 rows=1 width=4) (actual time=699.985..699.985 rows=1 loops=1)
           Buffers: shared hit=34308 read=2035
           ->  Bitmap Heap Scan on customer  (cost=6649.43..51965.22 rows=382392 width=4) (actual time=122.790..581.576 rows=381729 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{22,23,28,17,24,19,21}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=34308 read=2035
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6553.83 rows=382392 width=0) (actual time=111.903..111.903 rows=381729 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{22,23,28,17,24,19,21}'::text[]))
                       Buffers: shared hit=317 read=748
   ->  HashAggregate  (cost=640669.12..640669.16 rows=3 width=20) (actual time=17066.676..17066.677 rows=7 loops=1)
         Buffers: shared hit=322528 read=4073 written=3
         ->  Hash Anti Join  (cost=596630.92..640226.17 rows=59060 width=20) (actual time=16252.342..17023.452 rows=63206 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=322528 read=4073 written=3
               ->  Bitmap Heap Scan on customer  (cost=2911.22..41870.18 rows=140227 width=24) (actual time=804.244..1172.311 rows=190616 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{22,23,28,17,24,19,21}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=69632 read=2432
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2876.17 rows=140227 width=0) (actual time=791.531..791.531 rows=190616 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{22,23,28,17,24,19,21}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=34472 read=2417
               ->  Hash  (cost=405283.20..405283.20 rows=15074920 width=4) (actual time=15435.674..15435.674 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=252893 read=1641 written=3
                     ->  Seq Scan on orders  (cost=0.00..405283.20 rows=15074920 width=4) (actual time=0.035..6870.680 rows=15015000 loops=1)
                           Buffers: shared hit=252893 read=1641 written=3
 Total runtime: 17221.715 ms
(30 rows)

COMMIT;
COMMIT