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
				('33', '24', '10', '28', '19', '27', '14')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('33', '24', '10', '28', '19', '27', '14')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=693952.57..693952.58 rows=3 width=20) (actual time=24349.713..24349.715 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=313817 read=12778 written=6
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52844.78..52844.79 rows=1 width=4) (actual time=1437.466..1437.467 rows=1 loops=1)
           Buffers: shared hit=35059 read=1283 written=1
           ->  Bitmap Heap Scan on customer  (cost=6633.21..51894.03 rows=380298 width=4) (actual time=247.515..1300.821 rows=381479 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{33,24,10,28,19,27,14}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=35059 read=1283 written=1
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6538.13 rows=380298 width=0) (actual time=235.238..235.238 rows=381479 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{33,24,10,28,19,27,14}'::text[]))
                       Buffers: shared hit=7 read=1057 written=1
   ->  HashAggregate  (cost=641107.72..641107.76 rows=3 width=20) (actual time=24349.632..24349.634 rows=7 loops=1)
         Buffers: shared hit=313815 read=12778 written=6
         ->  Hash Anti Join  (cost=596622.60..640665.37 rows=58980 width=20) (actual time=22952.760..24289.235 rows=63417 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=313815 read=12778 written=6
               ->  Bitmap Heap Scan on customer  (cost=2902.90..41840.41 rows=139410 width=24) (actual time=1541.907..2431.748 rows=190366 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{33,24,10,28,19,27,14}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=70239 read=1817 written=1
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2868.05 rows=139410 width=0) (actual time=1530.879..1530.879 rows=190366 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{33,24,10,28,19,27,14}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35069 read=1817 written=1
               ->  Hash  (cost=405283.20..405283.20 rows=15074920 width=4) (actual time=21400.003..21400.003 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=243573 read=10961 written=5
                     ->  Seq Scan on orders  (cost=0.00..405283.20 rows=15074920 width=4) (actual time=0.020..12504.456 rows=15015000 loops=1)
                           Buffers: shared hit=243573 read=10961 written=5
 Total runtime: 24511.647 ms
(30 rows)

COMMIT;
COMMIT