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
				('24', '11', '25', '19', '20', '27', '15')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('24', '11', '25', '19', '20', '27', '15')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=694653.92..694653.92 rows=3 width=20) (actual time=17653.750..17653.750 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=140523 read=186554 written=78
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52856.98..52856.99 rows=1 width=4) (actual time=759.075..759.075 rows=1 loops=1)
           Buffers: shared hit=35251 read=1090
           ->  Bitmap Heap Scan on customer  (cost=6635.81..51905.40 rows=380632 width=4) (actual time=201.158..636.550 rows=381537 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{24,11,25,19,20,27,15}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=35251 read=1090
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6540.65 rows=380632 width=0) (actual time=181.323..181.323 rows=381537 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{24,11,25,19,20,27,15}'::text[]))
                       Buffers: shared hit=9 read=1054
   ->  HashAggregate  (cost=641796.86..641796.90 rows=3 width=20) (actual time=17653.670..17653.676 rows=7 loops=1)
         Buffers: shared hit=140521 read=186554 written=78
         ->  Hash Anti Join  (cost=597806.02..641355.68 rows=58823 width=20) (actual time=16555.341..17608.214 rows=63428 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=140521 read=186554 written=78
               ->  Bitmap Heap Scan on customer  (cost=2903.69..41843.30 rows=139490 width=24) (actual time=861.782..1563.339 rows=190442 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{24,11,25,19,20,27,15}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=35263 read=36768
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2868.82 rows=139490 width=0) (actual time=848.968..848.968 rows=190442 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{24,11,25,19,20,27,15}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35261 read=1624
               ->  Hash  (cost=406090.48..406090.48 rows=15104948 width=4) (actual time=15685.121..15685.121 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=105255 read=149786 written=78
                     ->  Seq Scan on orders  (cost=0.00..406090.48 rows=15104948 width=4) (actual time=0.030..7541.387 rows=15015000 loops=1)
                           Buffers: shared hit=105255 read=149786 written=78
 Total runtime: 17748.607 ms
(30 rows)

COMMIT;
COMMIT