START TRANSACTION;
auto commit mode: off
select
	cntrycode,
	count(*) as numcust,
	sum(c_acctbal) as totacctbal
from
	(
		select
			substring(c_phone, 1, 2) as cntrycode,
			c_acctbal
		from
			customer
		where
			substring(c_phone, 1, 2) in
				('18', '31', '34', '17', '29', '32', '30')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substring(c_phone, 1, 2) in
						('18', '31', '34', '17', '29', '32', '30')
			)
			and not exists (
				select
					*
				from
					orders
				where
+-----------+---------+------------+
| cntrycode | numcust | totacctbal |
+===========+=========+============+
+-----------+---------+------------+
0 tuples
COMMIT;
auto commit mode: on