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', '70ccae0c2ed0f3f097e393ef6c997bc5', '216.73.216.132', '1759445275', '1759445275', '/shop/product_info.php?info=p109_.html')

[XT SQL Error]