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', 'de5g1cfrimo50lale5kpcq0j11', '216.73.216.9', '1758178308', '1758178308', '/index.php?XTCsid=96e5a14b1aa2db44cddf9aa911838531')

[XT SQL Error]