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', 'ce79607bff9b4aa3028395df05b0d2cd', '216.73.216.132', '1759445190', '1759445190', '/shop/product_info.php?info=p7_.html')

[XT SQL Error]