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
				('27', '19', '22', '11', '25', '26', '24')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('27', '19', '22', '11', '25', '26', '24')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=698087.31..698087.32 rows=3 width=20) (actual time=21694.371..21694.371 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=326784 read=1586 written=207
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52844.26..52844.27 rows=1 width=4) (actual time=1313.663..1313.663 rows=1 loops=1)
           Buffers: shared hit=35289 read=1051 written=113
           ->  Bitmap Heap Scan on customer  (cost=6633.10..51893.55 rows=380284 width=4) (actual time=242.695..1167.693 rows=380678 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{27,19,22,11,25,26,24}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=35289 read=1051 written=113
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6538.03 rows=380284 width=0) (actual time=229.282..229.282 rows=380678 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{27,19,22,11,25,26,24}'::text[]))
                       Buffers: shared hit=11 read=1051 written=113
   ->  HashAggregate  (cost=645242.97..645243.02 rows=3 width=20) (actual time=21694.280..21694.282 rows=7 loops=1)
         Buffers: shared hit=326782 read=1586 written=207
         ->  Hash Anti Join  (cost=600758.18..644800.64 rows=58978 width=20) (actual time=20376.354..21637.721 rows=63166 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=326782 read=1586 written=207
               ->  Bitmap Heap Scan on customer  (cost=2902.83..41840.21 rows=139405 width=24) (actual time=1471.351..2241.618 rows=190157 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{27,19,22,11,25,26,24}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=70472 read=1586 written=207
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2867.98 rows=139405 width=0) (actual time=1453.290..1453.290 rows=190157 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{27,19,22,11,25,26,24}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35299 read=1586 written=207
               ->  Hash  (cost=408106.27..408106.27 rows=15179927 width=4) (actual time=18893.625..18893.625 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=256307
                     ->  Seq Scan on orders  (cost=0.00..408106.27 rows=15179927 width=4) (actual time=0.044..9780.049 rows=15015000 loops=1)
                           Buffers: shared hit=256307
 Total runtime: 21815.569 ms
(30 rows)

COMMIT;
COMMIT