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', 'hi4htl7080p1ra7mb1ee2kdmd3', '216.73.216.4', '1771219075', '1771219075', '/shop_content.php?XTCsid=ea749d82d78692dfdcc9ae5e35913621&coID=2')

[XT SQL Error]