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', 'c201f948f882ccd36b65cd7faa5dad9e', '216.73.216.37', '1774945023', '1774945023', '/')

[XT SQL Error]