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', 'e5b7fe358c4e1b6b117a2136761a522f', '216.73.216.132', '1759481550', '1759481550', '/shop/product_info.php?info=p103_.html')

[XT SQL Error]