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', 'u7tldfu6afjj057bk4jos9s5c1', '216.73.216.9', '1758056381', '1758056381', '/index.php?XTCsid=fba53dc6b549a2b9cad4403a2504e4ed&cat=c8_Disposable-tableware.html')

[XT SQL Error]