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', 'uaq3a24g35pad1ds5sgr0m5kb1', '216.73.216.244', '1752206827', '1752206827', '/index.php?cat=c6_Foodstuffs.html&XTCsid=c63b24e231384cad64f954428cedcfc2')

[XT SQL Error]