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', 'uv8ttocd77l18a4l8f642rndu5', '216.73.216.127', '1752881971', '1752881971', '/index.php?cat=c2_Decoration.html&XTCsid=cdfc0f2ea8be6cebe1f6056b0a37d83f')

[XT SQL Error]