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
				('17', '22', '20', '24', '14', '31', '34')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('17', '22', '20', '24', '14', '31', '34')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=694043.02..694043.03 rows=3 width=20) (actual time=17112.558..17112.559 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=315298 read=11554 written=1
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52846.34..52846.35 rows=1 width=4) (actual time=791.440..791.440 rows=1 loops=1)
           Buffers: shared hit=35279 read=1063
           ->  Bitmap Heap Scan on customer  (cost=6633.53..51895.48 rows=380341 width=4) (actual time=159.660..657.065 rows=381293 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{17,22,20,24,14,31,34}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=35279 read=1063
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6538.45 rows=380341 width=0) (actual time=146.909..146.909 rows=381293 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{17,22,20,24,14,31,34}'::text[]))
                       Buffers: shared hit=6 read=1058
   ->  HashAggregate  (cost=641196.60..641196.65 rows=3 width=20) (actual time=17112.480..17112.484 rows=7 loops=1)
         Buffers: shared hit=315296 read=11554 written=1
         ->  Hash Anti Join  (cost=597212.45..640755.77 rows=58778 width=20) (actual time=16517.143..17080.727 rows=63431 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=315296 read=11554 written=1
               ->  Bitmap Heap Scan on customer  (cost=2902.61..41839.42 rows=139383 width=24) (actual time=899.079..1107.578 rows=190686 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{17,22,20,24,14,31,34}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=70460 read=1600
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2867.77 rows=139383 width=0) (actual time=885.390..885.390 rows=190686 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{17,22,20,24,14,31,34}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35288 read=1600
               ->  Hash  (cost=405686.04..405686.04 rows=15089904 width=4) (actual time=15606.732..15606.732 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=244833 read=9954 written=1
                     ->  Seq Scan on orders  (cost=0.00..405686.04 rows=15089904 width=4) (actual time=0.045..6309.771 rows=15015000 loops=1)
                           Buffers: shared hit=244833 read=9954 written=1
 Total runtime: 17215.912 ms
(30 rows)

COMMIT;
COMMIT