1366 - Incorrect integer value: '' for column 'customer_id' at row 1

insert into whos_online (customer_id, full_name, session_id, ip_address, time_entry, time_last_click, last_page_url) values ('', 'Guest', 'd3c09adad3f2232c6a8e419ed8ace045', '216.73.216.132', '1759460258', '1759460258', '/shop/product_info.php?info=p119_.html')

[XT SQL Error]