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', 'kl9onlvjv597orbc1d5iucmpd4', '216.73.216.147', '1751746285', '1751746285', '/product_info.php?info=p16_Octoberfest-CD.html&XTCsid=33509f1bee4ee2cbb673a74e5faae0d4')

[XT SQL Error]