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', '10', '34', '20', '32', '11', '27')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('13', '10', '34', '20', '32', '11', '27')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=692901.29..692901.29 rows=3 width=20) (actual time=23619.378..23619.379 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=262450 read=64142 written=4206
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52876.40..52876.41 rows=1 width=4) (actual time=1176.816..1176.816 rows=1 loops=1)
           Buffers: shared hit=22550 read=13790
           ->  Bitmap Heap Scan on customer  (cost=6639.93..51923.49 rows=381164 width=4) (actual time=146.846..1051.763 rows=381347 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{13,10,34,20,32,11,27}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=22550 read=13790
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6544.64 rows=381164 width=0) (actual time=135.009..135.009 rows=381347 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{13,10,34,20,32,11,27}'::text[]))
                       Buffers: shared hit=9 read=1053
   ->  HashAggregate  (cost=640024.81..640024.85 rows=3 width=20) (actual time=23619.291..23619.293 rows=7 loops=1)
         Buffers: shared hit=262448 read=64142 written=4206
         ->  Hash Anti Join  (cost=596625.18..639585.79 rows=58536 width=20) (actual time=21841.606..23558.680 rows=63560 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=262448 read=64142 written=4206
               ->  Bitmap Heap Scan on customer  (cost=2905.48..41849.64 rows=139663 width=24) (actual time=1311.223..2535.010 rows=190461 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{13,10,34,20,32,11,27}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=22562 read=49491 written=4178
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2870.57 rows=139663 width=0) (actual time=1299.040..1299.040 rows=190461 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{13,10,34,20,32,11,27}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=22560 read=14326
               ->  Hash  (cost=405283.20..405283.20 rows=15074920 width=4) (actual time=20521.788..20521.788 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=239883 read=14651 written=28
                     ->  Seq Scan on orders  (cost=0.00..405283.20 rows=15074920 width=4) (actual time=0.035..7603.102 rows=15015000 loops=1)
                           Buffers: shared hit=239883 read=14651 written=28
 Total runtime: 23799.773 ms
(30 rows)

COMMIT;
COMMIT