how many orders did the person with the most orders have?
select count ( * ) from orders group by customer_id order by count ( * ) desc limit 1
who was that person? Give me the id.
select customer_id from orders group by customer_id order by count ( * ) desc limit 1
can you give me the last name, id, and phone number of the person with the most order?
select t1.customer_last_name, t1.customer_id, t1.phone_number from customers as t1 join orders as t2 on t1.customer_id = t2.customer_id group by t2.customer_id order by count ( * ) desc limit 1