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', 'esj0fd7683p31a3pmgpmtl8tu1', '216.73.216.176', '1762334834', '1762334834', '/product_info.php?XTCsid=38717c4dd62e88001622b2c7b8b8372a&info=p11_Fan-for-decorations.html')

[XT SQL Error]