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', 'l16e40o356r0u435gbk4tk62s4', '216.73.216.165', '1752301610', '1752301610', '/shop_content.php?coID=4&XTCsid=53b3ca17e11023a1f7ae6e1aa45a0ce7')

[XT SQL Error]