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', 'accbshk10s5pgd87uag7i4cap4', '216.73.216.155', '1767594121', '1767594121', '/product_info.php?XTCsid=07630e5b15e9155d8246af3ee660ca0e&info=p14_65-drinking-cups-1-2-Liter.html')

[XT SQL Error]