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', 'fvu0vsq1tr8936gchue3ornkq0', '216.73.217.78', '1791214978', '1791214978', '/shop_content.php?XTCsid=98fab66f7c5bcfa7f4c82f0bdb1cf869&coID=2')

[XT SQL Error]