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', '9e2okoc6bbhmepr2f9mi8s5s72', '216.73.216.83', '1760471801', '1760471801', '/xtshop/product_info.php?info=p779_.html')

[XT SQL Error]