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', 'v5rgd3jdtv8j80h61r38bob992', '216.73.217.89', '1789577800', '1789577800', '/index.php?XTCsid=cc9bbfbe9121132c07494a23739109f1')

[XT SQL Error]