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
				('30', '33', '31', '10', '32', '18', '14')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('30', '33', '31', '10', '32', '18', '14')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=693467.33..693467.33 rows=3 width=20) (actual time=13361.476..13361.477 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=323848 read=3007 written=1
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52860.33..52860.34 rows=1 width=4) (actual time=631.900..631.901 rows=1 loops=1)
           Buffers: shared hit=35186 read=1158
           ->  Bitmap Heap Scan on customer  (cost=6636.51..51908.52 rows=380724 width=4) (actual time=156.799..535.788 rows=382019 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{30,33,31,10,32,18,14}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=35186 read=1158
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6541.33 rows=380724 width=0) (actual time=143.858..143.858 rows=382019 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{30,33,31,10,32,18,14}'::text[]))
                       Buffers: shared hit=10 read=1056
   ->  HashAggregate  (cost=640606.92..640606.96 rows=3 width=20) (actual time=13361.409..13361.412 rows=7 loops=1)
         Buffers: shared hit=323846 read=3007 written=1
         ->  Hash Anti Join  (cost=597215.18..640162.78 rows=59218 width=20) (actual time=12651.142..13317.086 rows=63995 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=323846 read=3007 written=1
               ->  Bitmap Heap Scan on customer  (cost=2905.34..41849.15 rows=139650 width=24) (actual time=700.392..932.046 rows=190823 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{30,33,31,10,32,18,14}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=70328 read=1735
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2870.43 rows=139650 width=0) (actual time=691.244..691.244 rows=190823 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{30,33,31,10,32,18,14}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=35196 read=1696
               ->  Hash  (cost=405686.04..405686.04 rows=15089904 width=4) (actual time=11936.773..11936.773 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=253515 read=1272 written=1
                     ->  Seq Scan on orders  (cost=0.00..405686.04 rows=15089904 width=4) (actual time=0.039..5437.537 rows=15015000 loops=1)
                           Buffers: shared hit=253515 read=1272 written=1
 Total runtime: 13504.099 ms
(30 rows)

COMMIT;
COMMIT