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
				('26', '31', '10', '24', '32', '16', '15')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('26', '31', '10', '24', '32', '16', '15')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                              QUERY PLAN                                                                              
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=693995.61..693995.61 rows=3 width=20) (actual time=23385.409..23385.411 rows=7 loops=1)
   Sort Key: (substr((public.customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=188947 read=138149 written=38
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52815.86..52815.87 rows=1 width=4) (actual time=2156.636..2156.636 rows=1 loops=1)
           Buffers: shared hit=13 read=36330
           ->  Bitmap Heap Scan on customer  (cost=6611.31..51865.72 rows=380054 width=4) (actual time=259.569..2028.082 rows=381973 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{26,31,10,24,32,16,15}'::text[])) AND (c_acctbal > 0::double precision))
                 Buffers: shared hit=13 read=36330
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6516.29 rows=380054 width=0) (actual time=244.186..244.186 rows=381973 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{26,31,10,24,32,16,15}'::text[]))
                       Buffers: shared hit=10 read=1055
   ->  HashAggregate  (cost=641179.67..641179.71 rows=3 width=20) (actual time=23385.339..23385.343 rows=7 loops=1)
         Buffers: shared hit=188945 read=138149 written=38
         ->  Hash Anti Join  (cost=597803.65..640741.92 rows=58366 width=20) (actual time=22205.654..23328.854 rows=63232 loops=1)
               Hash Cond: (public.customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=188945 read=138149 written=38
               ->  Bitmap Heap Scan on customer  (cost=2901.32..41834.82 rows=139257 width=24) (actual time=2312.894..2966.710 rows=191049 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{26,31,10,24,32,16,15}'::text[])) AND (c_acctbal > $0))
                     Buffers: shared hit=31880 read=40170
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2866.51 rows=139257 width=0) (actual time=2300.931..2300.931 rows=191049 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{26,31,10,24,32,16,15}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=24 read=36867
               ->  Hash  (cost=406090.48..406090.48 rows=15104948 width=4) (actual time=19881.113..19881.113 rows=15015000 loops=1)
                     Buckets: 2097152  Batches: 1  Memory Usage: 527872kB
                     Buffers: shared hit=157062 read=97979 written=38
                     ->  Seq Scan on orders  (cost=0.00..406090.48 rows=15104948 width=4) (actual time=0.174..10480.371 rows=15015000 loops=1)
                           Buffers: shared hit=157062 read=97979 written=38
 Total runtime: 23517.038 ms
(30 rows)

COMMIT;
COMMIT