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
				('24', '23', '32', '16', '21', '14', '17')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('24', '23', '32', '16', '21', '14', '17')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=693556.96..693556.97 rows=3 width=20) (actual time=17308.521..17308.522 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=324569 read=2284
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52915.24..52915.25 rows=1 width=4) (actual time=1228.206..1228.206 rows=1 loops=1)
           Buffers: shared hit=35287 read=1056
           ->  Bitmap Heap Scan on customer  (cost=6648.18..51959.66 rows=382228 width=4) (actual time=241.069..1086.455 rows=382007 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{24,23,32,16,21,14,17}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=35287 read=1056
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6552.62 rows=382228 width=0) (actual time=222.899..222.899 rows=382007 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{24,23,32,16,21,14,17}'::text[]))
                       Buffers: shared hit=9 read=1056
   ->  HashAggregate  (cost=640641.65..640641.69 rows=3 width=20) (actual time=17308.441..17308.443 rows=7 loops=1)
         Buffers: shared hit=324567 read=2284
         ->  Hash Anti Join  (cost=597219.34..640201.41 rows=58699 width=20) (actual time=16689.046..17278.701 rows=63213 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=324567 read=2284
               ->  Bitmap Heap Scan on customer  (cost=2909.50..41863.89 rows=140053 width=24) (actual time=1347.105..1591.319 rows=190800 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{24,23,32,16,21,14,17}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=70467 read=1594
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2874.49 rows=140053 width=0) (actual time=1331.445..1331.445 rows=190800 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{24,23,32,16,21,14,17}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35296 read=1594
               ->  Hash  (cost=405686.04..405686.04 rows=15089904 width=4) (actual time=15326.732..15326.732 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=254097 read=690
                     ->  Seq Scan on orders  (cost=0.00..405686.04 rows=15089904 width=4) (actual time=0.032..6728.218 rows=15015000 loops=1)
                           Buffers: shared hit=254097 read=690
 Total runtime: 17430.806 ms
(30 rows)

COMMIT;
COMMIT