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', 'hv2ujnl9pk2u28dvn1te73qh61', '216.73.216.178', '1768787224', '1768787224', '/product_info.php?XTCsid=792dd2eece839333bab562194e3fb545&info=p19_10-Paper-Plates.html')

[XT SQL Error]