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', 'd4bb6bf292060db31924ddf343df65a6', '216.73.216.42', '1763354606', '1763354606', '/shop/product_info.php?XTCsid=041c8fc0413f2441df67fe52a6815a15&info=p122_.html')

[XT SQL Error]