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', '2rc047ld15dj6qsua0ahio58i3', '216.73.216.141', '1751423289', '1751423289', '/index.php?XTCsid=935b3fdff77aef65cd9fe37ae67353da')

[XT SQL Error]