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', 'h5p7ummo9mtrpakvfq6enndc17', '216.73.216.28', '1775763892', '1775763892', '/index.php?XTCsid=3547ee950f9337e348e5e07def1466f0&cat=c9_Tabledeko.html')

[XT SQL Error]