Testa den här frågan
Select customer_id,last_name From Customer
Where customer_id in
(Select customer_id From Order group by customer_id having count(customer_id) > 2 )
Testa den här frågan
Select customer_id,last_name From Customer
Where customer_id in
(Select customer_id From Order group by customer_id having count(customer_id) > 2 )