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', '6be9e085408d5b9b3677ba3602222533', '216.73.216.219', '1772242444', '1772242444', '/shop/login.php?XTCsid=041c8fc0413f2441df67fe52a6815a15')

[XT SQL Error]