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', 'b9l39krj59o0fni3rahvj5qe22', '216.73.216.72', '1787313202', '1787313202', '/index.php?XTCsid=72205775904d1a5c41b590dd7b5ff1d6&cat=c12_Music.html')

[XT SQL Error]