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', 'lehf4b0bmmce13sc6onhfbjnk4', '216.73.216.167', '1762573899', '1762573899', '/product_info.php?XTCsid=1ce6d0a6925740e42ccf6986944a240a&info=p17_20-Tissue-Napkins.html')

[XT SQL Error]