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
				('33', '16', '18', '19', '28', '10', '30')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('33', '16', '18', '19', '28', '10', '30')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=697791.41..697791.41 rows=3 width=20) (actual time=20924.890..20924.891 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=171323 read=157292 written=108
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52967.00..52967.01 rows=1 width=4) (actual time=1641.576..1641.576 rows=1 loops=1)
           Buffers: shared hit=10 read=36336 written=74
           ->  Bitmap Heap Scan on customer  (cost=6678.09..52009.53 rows=382988 width=4) (actual time=197.744..1512.790 rows=382477 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{33,16,18,19,28,10,30}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=10 read=36336 written=74
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6582.34 rows=382988 width=0) (actual time=180.958..180.958 rows=382477 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{33,16,18,19,28,10,30}'::text[]))
                       Buffers: shared hit=8 read=1060 written=4
   ->  HashAggregate  (cost=644824.33..644824.38 rows=3 width=20) (actual time=20924.808..20924.812 rows=7 loops=1)
         Buffers: shared hit=171321 read=157292 written=108
         ->  Hash Anti Join  (cost=601385.80..644383.21 rows=58816 width=20) (actual time=19921.046..20879.090 rows=63912 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=171321 read=157292 written=108
               ->  Bitmap Heap Scan on customer  (cost=2940.30..41902.01 rows=140332 width=24) (actual time=1755.687..2331.363 rows=191026 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{33,16,18,19,28,10,30}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=35176 read=36874 written=74
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2905.22 rows=140332 width=0) (actual time=1741.553..1741.553 rows=191026 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{33,16,18,19,28,10,30}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=19 read=36874 written=74
               ->  Hash  (cost=408509.11..408509.11 rows=15194911 width=4) (actual time=18138.231..18138.231 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=136142 read=120418 written=34
                     ->  Seq Scan on orders  (cost=0.00..408509.11 rows=15194911 width=4) (actual time=0.048..9922.093 rows=15015000 loops=1)
                           Buffers: shared hit=136142 read=120418 written=34
 Total runtime: 21057.938 ms
(30 rows)

COMMIT;
COMMIT