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', 'dhh1ut9b01sgnegf6g710hjph6', '216.73.216.180', '1766662803', '1766662803', '/index.php?XTCsid=3f98699a7205aa16d7f8014dc7c0d34a&cat=c4_Beer-Mugs.html')

[XT SQL Error]