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
				('14', '28', '23', '12', '15', '32', '24')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('14', '28', '23', '12', '15', '32', '24')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=694247.96..694247.97 rows=3 width=20) (actual time=28958.987..28958.987 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=288035 read=38818 written=1
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52961.89..52961.90 rows=1 width=4) (actual time=3993.717..3993.718 rows=1 loops=1)
           Buffers: shared hit=12 read=36331
           ->  Bitmap Heap Scan on customer  (cost=6677.01..52004.77 rows=382848 width=4) (actual time=280.385..3860.616 rows=381797 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{14,28,23,12,15,32,24}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=12 read=36331
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6581.29 rows=382848 width=0) (actual time=269.945..269.945 rows=381797 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{14,28,23,12,15,32,24}'::text[]))
                       Buffers: shared hit=9 read=1056
   ->  HashAggregate  (cost=641286.00..641286.04 rows=3 width=20) (actual time=28958.908..28958.909 rows=7 loops=1)
         Buffers: shared hit=288033 read=38818 written=1
         ->  Hash Anti Join  (cost=597250.35..640838.28 rows=59696 width=20) (actual time=27208.078..28904.885 rows=63170 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=288033 read=38818 written=1
               ->  Bitmap Heap Scan on customer  (cost=2940.51..41902.78 rows=140353 width=24) (actual time=4185.633..5489.957 rows=190661 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{14,28,23,12,15,32,24}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=35189 read=36872 written=1
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2905.43 rows=140353 width=0) (actual time=4167.520..4167.520 rows=190661 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{14,28,23,12,15,32,24}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=21 read=36869
               ->  Hash  (cost=405686.04..405686.04 rows=15089904 width=4) (actual time=23009.600..23009.600 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=252841 read=1946
                     ->  Seq Scan on orders  (cost=0.00..405686.04 rows=15089904 width=4) (actual time=0.038..14282.165 rows=15015000 loops=1)
                           Buffers: shared hit=252841 read=1946
 Total runtime: 29049.567 ms
(30 rows)

COMMIT;
COMMIT