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', 'jr9uansp2kd14opkjnp2qslvo6', '216.73.217.58', '1779468010', '1779468010', '/product_info.php?XTCsid=15cbbc13723f7bc63afaf1294f637517&info=p15_25-balloons.html')

[XT SQL Error]