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', 'ke0tafv7pi8oo58h8joe3qtuh5', '216.73.217.78', '1791260227', '1791260227', '/index.php?XTCsid=b96c312bc033b65ef2a12f33933bb1aa')

[XT SQL Error]