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', 'ifbla0umg2qqt6fv6bptsll8n4', '216.73.216.9', '1757940416', '1757940416', '/index.php?XTCsid=0832187515ca706758d8e1ce01e34faf&cat=c8_Disposable-tableware.html')

[XT SQL Error]