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
				('16', '29', '23', '14', '34', '11', '24')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('16', '29', '23', '14', '34', '11', '24')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=695354.14..695354.15 rows=3 width=20) (actual time=16883.551..16883.551 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=288702 read=38931
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52928.35..52928.36 rows=1 width=4) (actual time=971.935..971.936 rows=1 loops=1)
           Buffers: shared hit=35260 read=1082
           ->  Bitmap Heap Scan on customer  (cost=6650.95..51971.88 rows=382588 width=4) (actual time=270.340..840.028 rows=381201 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{16,29,23,14,34,11,24}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=35260 read=1082
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6555.30 rows=382588 width=0) (actual time=250.626..250.626 rows=381201 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{16,29,23,14,34,11,24}'::text[]))
                       Buffers: shared hit=8 read=1056
   ->  HashAggregate  (cost=642425.71..642425.75 rows=3 width=20) (actual time=16883.445..16883.447 rows=7 loops=1)
         Buffers: shared hit=288700 read=38931
         ->  Hash Anti Join  (cost=598995.73..641985.05 rows=58755 width=20) (actual time=15398.481..16823.312 rows=63265 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=288700 read=38931
               ->  Bitmap Heap Scan on customer  (cost=2910.79..41868.65 rows=140185 width=24) (actual time=1119.725..2104.067 rows=190469 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{16,29,23,14,34,11,24}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=35272 read=36808
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2875.75 rows=140185 width=0) (actual time=1098.509..1098.509 rows=190469 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{16,29,23,14,34,11,24}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35270 read=1619
               ->  Hash  (cost=406897.75..406897.75 rows=15134975 width=4) (actual time=14269.649..14269.649 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=253425 read=2123
                     ->  Seq Scan on orders  (cost=0.00..406897.75 rows=15134975 width=4) (actual time=0.039..7087.603 rows=15015000 loops=1)
                           Buffers: shared hit=253425 read=2123
 Total runtime: 17062.641 ms
(30 rows)

COMMIT;
COMMIT