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', 'g0immi5ebu09ablfa5mr8djc66', '216.73.216.9', '1757811389', '1757811389', '/shop_content.php?XTCsid=67a1ee4a966bad4e2954e4e321814afb&coID=7')

[XT SQL Error]