586. Customer Placing the Largest Number of Orders

https://leetcode.com/articles/customer-placing-the-largest-number-of-orders/

--It can handle the case where more than one customer can have maximum number of orders.

select customer_number from orders

group by customer_number

having count(order_number) in

(

select count(order_number) from orders

group by customer_number

order by count(order_number) desc

limit 1

);