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', 'brhqr8a4656hn44ckv1uvnc4c1', '216.73.216.222', '1765952041', '1765952041', '/product_info.php?XTCsid=792dd2eece839333bab562194e3fb545&info=p12_33-feet-crape-paper.html')

[XT SQL Error]