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
				('22', '33', '15', '26', '24', '20', '23')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('22', '33', '15', '26', '24', '20', '23')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=697064.37..697064.38 rows=3 width=20) (actual time=13086.248..13086.249 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=222417 read=105701 written=17
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52877.76..52877.77 rows=1 width=4) (actual time=820.826..820.827 rows=1 loops=1)
           Buffers: shared hit=11 read=36333
           ->  Bitmap Heap Scan on customer  (cost=6640.20..51924.76 rows=381202 width=4) (actual time=100.929..743.313 rows=381789 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{22,33,15,26,24,20,23}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=11 read=36333
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6544.90 rows=381202 width=0) (actual time=91.706..91.706 rows=381789 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{22,33,15,26,24,20,23}'::text[]))
                       Buffers: shared hit=9 read=1057
   ->  HashAggregate  (cost=644186.53..644186.58 rows=3 width=20) (actual time=13086.166..13086.170 rows=7 loops=1)
         Buffers: shared hit=222415 read=105701 written=17
         ->  Hash Anti Join  (cost=600173.21..643742.46 rows=59210 width=20) (actual time=12029.467..13045.284 rows=63341 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=222415 read=105701 written=17
               ->  Bitmap Heap Scan on customer  (cost=2907.99..41858.63 rows=139910 width=24) (actual time=887.456..1499.854 rows=190948 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{22,33,15,26,24,20,23}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=23 read=72036
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2873.02 rows=139910 width=0) (actual time=878.224..878.224 rows=190948 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{22,33,15,26,24,20,23}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=21 read=36870
               ->  Hash  (cost=407703.43..407703.43 rows=15164943 width=4) (actual time=11131.143..11131.143 rows=15000000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527344kB
                     Buffers: shared hit=222389 read=33665 written=17
                     ->  Seq Scan on orders  (cost=0.00..407703.43 rows=15164943 width=4) (actual time=0.023..5072.492 rows=15000000 loops=1)
                           Buffers: shared hit=222389 read=33665 written=17
 Total runtime: 13199.255 ms
(30 rows)

COMMIT;
COMMIT