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', 'djf1o7lp11usidpu0tsgag9h15', '216.73.216.244', '1752218578', '1752218578', '/index.php?cat=c2_Decoration.html&XTCsid=38f09672db884903e3803adf9d076819')

[XT SQL Error]