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', 'kphg35vcvfk8i6nmf41aildml4', '216.73.216.9', '1758183088', '1758183088', '/index.php?XTCsid=f62d5eebf71271f50348b97ac1df1150')

[XT SQL Error]