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', '0ke84p8l83m46ok1ingnmgfv23', '216.73.216.25', '1782984344', '1782984344', '/xtshop/index.php?cat=c7_.html')

[XT SQL Error]