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', '2inikca6g3ks716is5gk8oui13', '216.73.216.147', '1751742673', '1751742673', '/shop_content.php?coID=2&XTCsid=ea749d82d78692dfdcc9ae5e35913621')

[XT SQL Error]