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
				('13', '20', '29', '15', '25', '17', '14')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('13', '20', '29', '15', '25', '17', '14')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=693591.51..693591.51 rows=3 width=20) (actual time=25912.400..25912.401 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=289481 read=37113 dirtied=252 written=44
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52929.54..52929.55 rows=1 width=4) (actual time=1411.421..1411.421 rows=1 loops=1)
           Buffers: shared hit=35287 read=1056 written=37
           ->  Bitmap Heap Scan on customer  (cost=6651.22..51972.99 rows=382620 width=4) (actual time=264.199..1281.675 rows=382244 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{13,20,29,15,25,17,14}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=35287 read=1056 written=37
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6555.56 rows=382620 width=0) (actual time=243.119..243.119 rows=382244 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{13,20,29,15,25,17,14}'::text[]))
                       Buffers: shared hit=9 read=1056 written=37
   ->  HashAggregate  (cost=640661.88..640661.93 rows=3 width=20) (actual time=25912.318..25912.323 rows=7 loops=1)
         Buffers: shared hit=289479 read=37113 dirtied=252 written=44
         ->  Hash Anti Join  (cost=596631.42..640214.43 rows=59661 width=20) (actual time=22299.197..25845.464 rows=63716 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=289479 read=37113 dirtied=252 written=44
               ->  Bitmap Heap Scan on customer  (cost=2911.72..41871.81 rows=140270 width=24) (actual time=1559.583..4620.952 rows=190890 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{13,20,29,15,25,17,14}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=35299 read=36756 written=44
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2876.66 rows=140270 width=0) (actual time=1549.412..1549.412 rows=190890 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{13,20,29,15,25,17,14}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35297 read=1594 written=37
               ->  Hash  (cost=405283.20..405283.20 rows=15074920 width=4) (actual time=20727.796..20727.796 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=254177 read=357 dirtied=252
                     ->  Seq Scan on orders  (cost=0.00..405283.20 rows=15074920 width=4) (actual time=0.021..12762.533 rows=15015000 loops=1)
                           Buffers: shared hit=254177 read=357 dirtied=252
 Total runtime: 26021.406 ms
(30 rows)

COMMIT;
COMMIT