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', 'nbn1tpasie60fre899jl4b31b2', '216.73.216.87', '1769305946', '1769305946', '/index.php?XTCsid=80c3e9fc87b53cb0d288d19ef4e9b63c&cat=c5_Crockery.html')

[XT SQL Error]