SELECT T1.customer_name FROM customers AS T1 JOIN customer_orders AS T2 ON T1.customer_id  =  T2.customer_id GROUP BY T1.customer_id ORDER BY count(*) DESC LIMIT 1
Show the name of the customer who has the most orders.
[Schema (values) (types)]: | customers_and_products_contacts |  Addresses : address_id (text) , line_1_number_building (number) , city (text) , zip_postcode (text) , state_province_county (text) , country (text) | Products : product_id (text) , product_type_code (number) , product_name (text) , product_price (text) | Customers : customer_id (text) , payment_method_code (number) , customer_number (text) , customer_name (text) , customer_address (text) , customer_phone (text) , customer_email (text) | Contacts : contact_id (text) , customer_id (number) , gender (text) , first_name (text) , last_name (text) , contact_phone (text) | Customer_Address_History : customer_id (text) , address_id (number) , date_from (text) , date_to (text) | Customer_Orders : order_id (text) , customer_id (number) , order_date (text) , order_status_code (text) | Order_Items : order_item_id (text) , order_id (number) , product_id (text) , order_quantity (text);