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
				('27', '29', '18', '17', '32', '16', '22')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('27', '29', '18', '17', '32', '16', '22')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=693399.81..693399.82 rows=3 width=20) (actual time=17779.234..17779.235 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=254079 read=72518 written=3031
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52803.96..52803.97 rows=1 width=4) (actual time=1320.293..1320.293 rows=1 loops=1)
           Buffers: shared hit=11 read=36333
           ->  Bitmap Heap Scan on customer  (cost=6608.81..51854.64 rows=379727 width=4) (actual time=235.161..1208.094 rows=381996 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{27,29,18,17,32,16,22}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=11 read=36333
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6513.88 rows=379727 width=0) (actual time=218.516..218.516 rows=381996 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{27,29,18,17,32,16,22}'::text[]))
                       Buffers: shared hit=9 read=1057
   ->  HashAggregate  (cost=640595.77..640595.82 rows=3 width=20) (actual time=17779.160..17779.162 rows=7 loops=1)
         Buffers: shared hit=254077 read=72518 written=3031
         ->  Hash Anti Join  (cost=596621.81..640151.98 rows=59172 width=20) (actual time=16340.664..17724.093 rows=63600 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=254077 read=72518 written=3031
               ->  Bitmap Heap Scan on customer  (cost=2902.11..41837.73 rows=139338 width=24) (actual time=1434.415..2359.173 rows=190814 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{27,29,18,17,32,16,22}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=23 read=72035 written=3031
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2867.28 rows=139338 width=0) (actual time=1422.066..1422.066 rows=190814 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{27,29,18,17,32,16,22}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=21 read=36871
               ->  Hash  (cost=405283.20..405283.20 rows=15074920 width=4) (actual time=14889.923..14889.923 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=254051 read=483
                     ->  Seq Scan on orders  (cost=0.00..405283.20 rows=15074920 width=4) (actual time=0.028..6588.484 rows=15015000 loops=1)
                           Buffers: shared hit=254051 read=483
 Total runtime: 17987.290 ms
(30 rows)

COMMIT;
COMMIT