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
				('25', '15', '17', '33', '10', '28', '18')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('25', '15', '17', '33', '10', '28', '18')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=696027.51..696027.52 rows=3 width=20) (actual time=16518.198..16518.198 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=282935 read=44664 dirtied=252 written=4
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52956.67..52956.68 rows=1 width=4) (actual time=1503.711..1503.712 rows=1 loops=1)
           Buffers: shared hit=15 read=36329
           ->  Bitmap Heap Scan on customer  (cost=6675.87..51999.90 rows=382706 width=4) (actual time=207.235..1377.362 rows=382602 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{25,15,17,33,10,28,18}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=15 read=36329
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6580.19 rows=382706 width=0) (actual time=178.007..178.007 rows=382602 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{25,15,17,33,10,28,18}'::text[]))
                       Buffers: shared hit=7 read=1059
   ->  HashAggregate  (cost=643070.76..643070.81 rows=3 width=20) (actual time=16518.113..16518.115 rows=7 loops=1)
         Buffers: shared hit=282933 read=44664 dirtied=252 written=4
         ->  Hash Anti Join  (cost=599025.38..642627.45 rows=59108 width=20) (actual time=15901.740..16466.259 rows=63733 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=282933 read=44664 dirtied=252 written=4
               ->  Bitmap Heap Scan on customer  (cost=2940.44..41902.42 rows=140342 width=24) (actual time=1690.619..1927.208 rows=190958 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{25,15,17,33,10,28,18}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=35180 read=36866
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2905.36 rows=140342 width=0) (actual time=1661.855..1661.855 rows=190958 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{25,15,17,33,10,28,18}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=25 read=36866
               ->  Hash  (cost=406897.75..406897.75 rows=15134975 width=4) (actual time=14195.837..14195.837 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=247750 read=7798 dirtied=252 written=4
                     ->  Seq Scan on orders  (cost=0.00..406897.75 rows=15134975 width=4) (actual time=0.046..7228.750 rows=15015000 loops=1)
                           Buffers: shared hit=247750 read=7798 dirtied=252 written=4
 Total runtime: 16601.649 ms
(30 rows)

COMMIT;
COMMIT