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', 'gd326cqmll45to0k9v0gchlbs1', '216.73.216.141', '1751417710', '1751417710', '/index.php?cat=c13_Accessoires.html&XTCsid=85f438a686cbfb5e3ea5e5d6b9611958')

[XT SQL Error]