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', 'ilbinp3g2k51vs0atkasis83q5', '216.73.217.173', '1788968146', '1788968146', '/index.php?XTCsid=935b3fdff77aef65cd9fe37ae67353da')

[XT SQL Error]