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
				('15', '14', '11', '22', '27', '21', '26')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('15', '14', '11', '22', '27', '21', '26')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=694089.58..694089.59 rows=3 width=20) (actual time=19359.956..19359.956 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=189959 read=136908 dirtied=253 written=34
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52868.68..52868.69 rows=1 width=4) (actual time=1247.279..1247.279 rows=1 loops=1)
           Buffers: shared hit=13 read=36329 written=16
           ->  Bitmap Heap Scan on customer  (cost=6638.30..51916.29 rows=380952 width=4) (actual time=152.451..1125.511 rows=381527 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{15,14,11,22,27,21,26}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=13 read=36329 written=16
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6543.07 rows=380952 width=0) (actual time=139.888..139.888 rows=381527 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{15,14,11,22,27,21,26}'::text[]))
                       Buffers: shared hit=11 read=1053
   ->  HashAggregate  (cost=641220.83..641220.87 rows=3 width=20) (actual time=19359.866..19359.869 rows=7 loops=1)
         Buffers: shared hit=189957 read=136908 dirtied=253 written=34
         ->  Hash Anti Join  (cost=597215.68..640779.55 rows=58837 width=20) (actual time=18584.682..19317.683 rows=63142 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=189957 read=136908 dirtied=253 written=34
               ->  Bitmap Heap Scan on customer  (cost=2905.84..41850.91 rows=139698 width=24) (actual time=1358.055..1713.503 rows=190615 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{15,14,11,22,27,21,26}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=35209 read=36866 written=16
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2870.92 rows=139698 width=0) (actual time=1344.794..1344.794 rows=190615 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{15,14,11,22,27,21,26}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=22 read=36866 written=16
               ->  Hash  (cost=405686.04..405686.04 rows=15089904 width=4) (actual time=17215.208..17215.208 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=154745 read=100042 dirtied=253 written=18
                     ->  Seq Scan on orders  (cost=0.00..405686.04 rows=15089904 width=4) (actual time=0.028..8326.171 rows=15015000 loops=1)
                           Buffers: shared hit=154745 read=100042 dirtied=253 written=18
 Total runtime: 19479.915 ms
(30 rows)

COMMIT;
COMMIT