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', '2a0eia3q65mrrhk8tr7rtrt861', '216.73.216.180', '1766769651', '1766769651', '/shop_content.php?XTCsid=792dd2eece839333bab562194e3fb545&coID=2')

[XT SQL Error]