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
				('26', '25', '15', '31', '30', '19', '22')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('26', '25', '15', '31', '30', '19', '22')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=698967.42..698967.43 rows=3 width=20) (actual time=19568.288..19568.289 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=325272 read=3606 written=355
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52951.73..52951.74 rows=1 width=4) (actual time=842.101..842.101 rows=1 loops=1)
           Buffers: shared hit=35238 read=1105
           ->  Bitmap Heap Scan on customer  (cost=6674.84..51995.30 rows=382570 width=4) (actual time=210.420..717.338 rows=381879 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{26,25,15,31,30,19,22}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=35238 read=1105
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6579.19 rows=382570 width=0) (actual time=192.101..192.101 rows=381879 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{26,25,15,31,30,19,22}'::text[]))
                       Buffers: shared hit=8 read=1058
   ->  HashAggregate  (cost=646015.61..646015.66 rows=3 width=20) (actual time=19568.209..19568.213 rows=7 loops=1)
         Buffers: shared hit=325270 read=3606 written=355
         ->  Hash Anti Join  (cost=601976.51..645568.49 rows=59616 width=20) (actual time=18645.176..19514.518 rows=63588 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=325270 read=3606 written=355
               ->  Bitmap Heap Scan on customer  (cost=2940.87..41903.90 rows=140382 width=24) (actual time=969.771..1350.573 rows=191022 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{26,25,15,31,30,19,22}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=68458 read=3602 written=355
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2905.78 rows=140382 width=0) (actual time=951.260..951.260 rows=191022 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{26,25,15,31,30,19,22}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35247 read=1644
               ->  Hash  (cost=408911.95..408911.95 rows=15209895 width=4) (actual time=17656.943..17656.943 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=256809 read=4
                     ->  Seq Scan on orders  (cost=0.00..408911.95 rows=15209895 width=4) (actual time=0.043..6635.705 rows=15015000 loops=1)
                           Buffers: shared hit=256809 read=4
 Total runtime: 19815.541 ms
(30 rows)

COMMIT;
COMMIT