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', 'm0jqqic8mbpm8o2jrrf6upqh22', '216.73.216.245', '1752391045', '1752391045', '/xtshop/create_account.php')

[XT SQL Error]