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
				('11', '10', '34', '29', '12', '23', '27')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('11', '10', '34', '29', '12', '23', '27')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=699497.58..699497.59 rows=3 width=20) (actual time=28563.641..28563.642 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=277038 read=52068
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52929.54..52929.55 rows=1 width=4) (actual time=2492.498..2492.499 rows=1 loops=1)
           Buffers: shared hit=25102 read=11238
           ->  Bitmap Heap Scan on customer  (cost=6651.22..51972.99 rows=382620 width=4) (actual time=291.452..2354.496 rows=380924 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{11,10,34,29,12,23,27}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=25102 read=11238
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6555.56 rows=382620 width=0) (actual time=275.885..275.885 rows=380924 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{11,10,34,29,12,23,27}'::text[]))
                       Buffers: shared hit=9 read=1053
   ->  HashAggregate  (cost=646567.96..646568.01 rows=3 width=20) (actual time=28563.552..28563.556 rows=7 loops=1)
         Buffers: shared hit=277036 read=52068
         ->  Hash Anti Join  (cost=602537.50..646120.50 rows=59661 width=20) (actual time=26068.763..28503.658 rows=63419 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=277036 read=52068
               ->  Bitmap Heap Scan on customer  (cost=2911.72..41871.81 rows=140270 width=24) (actual time=2649.607..4691.781 rows=190233 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{11,10,34,29,12,23,27}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=46988 read=25047
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2876.66 rows=140270 width=0) (actual time=2633.914..2633.914 rows=190233 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{11,10,34,29,12,23,27}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=25112 read=11774
               ->  Hash  (cost=409314.79..409314.79 rows=15224879 width=4) (actual time=23407.410..23407.410 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=230045 read=27021
                     ->  Seq Scan on orders  (cost=0.00..409314.79 rows=15224879 width=4) (actual time=0.022..15789.778 rows=15015000 loops=1)
                           Buffers: shared hit=230045 read=27021
 Total runtime: 28641.301 ms
(30 rows)

COMMIT;
COMMIT