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', 'igfge0qlaen9qc6tmntc8nq675', '216.73.216.147', '1751744297', '1751744297', '/index.php?cat=c9_Tabledeko.html&XTCsid=25e3a9d33bac206ca2799e0bee35f2b1')

[XT SQL Error]