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', 'uc111o8f34ulav0u3ar63vbr23', '216.73.216.244', '1752210116', '1752210116', '/index.php?cat=c6_Foodstuffs.html&XTCsid=c63b24e231384cad64f954428cedcfc2')

[XT SQL Error]