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', '6re0a7cehttc53or5i84o5n465', '216.73.216.165', '1752393657', '1752393657', '/shop_content.php?coID=3&XTCsid=38717c4dd62e88001622b2c7b8b8372a')

[XT SQL Error]