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
				('32', '12', '14', '34', '26', '16', '30')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('32', '12', '14', '34', '26', '16', '30')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=694055.62..694055.62 rows=3 width=20) (actual time=23858.067..23858.067 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=97669 read=229451 written=38
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52859.59..52859.60 rows=1 width=4) (actual time=1840.053..1840.053 rows=1 loops=1)
           Buffers: shared hit=9 read=36335
           ->  Bitmap Heap Scan on customer  (cost=6636.35..51907.83 rows=380704 width=4) (actual time=191.560..1711.964 rows=381813 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{32,12,14,34,26,16,30}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=9 read=36335
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6541.18 rows=380704 width=0) (actual time=179.839..179.839 rows=381813 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{32,12,14,34,26,16,30}'::text[]))
                       Buffers: shared hit=6 read=1060
   ->  HashAggregate  (cost=641195.94..641195.99 rows=3 width=20) (actual time=23857.999..23858.003 rows=7 loops=1)
         Buffers: shared hit=97667 read=229451 written=38
         ->  Hash Anti Join  (cost=597806.09..640757.45 rows=58466 width=20) (actual time=22483.764..23808.471 rows=63561 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=97667 read=229451 written=38
               ->  Bitmap Heap Scan on customer  (cost=2903.76..41843.50 rows=139495 width=24) (actual time=1957.834..2873.029 rows=191070 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{32,12,14,34,26,16,30}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=21 read=72053
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2868.89 rows=139495 width=0) (actual time=1944.149..1944.149 rows=191070 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{32,12,14,34,26,16,30}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=18 read=36875
               ->  Hash  (cost=406090.48..406090.48 rows=15104948 width=4) (actual time=20516.660..20516.660 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=97643 read=157398 written=38
                     ->  Seq Scan on orders  (cost=0.00..406090.48 rows=15104948 width=4) (actual time=0.056..11820.417 rows=15015000 loops=1)
                           Buffers: shared hit=97643 read=157398 written=38
 Total runtime: 23974.531 ms
(30 rows)

COMMIT;
COMMIT