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', 'kckcofi90pd04rmauhkl48ncm6', '216.73.216.130', '1760912826', '1760912826', '/index.php?XTCsid=1ea6ae83a06864ae88742e98ecbda16e&cat=c4_Beer-Mugs.html')

[XT SQL Error]