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', 'c3jmvbf46fsttj9bru3eheo024', '216.73.216.80', '1751322059', '1751322059', '/index.php?language=en&XTCsid=38f09672db884903e3803adf9d076819')

[XT SQL Error]