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', '226c5f546f544a6ca898d949dab0ec84', '216.73.216.132', '1759445405', '1759445405', '/shop/product_info.php?info=p130_.html')

[XT SQL Error]