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', '7r9epgdj09tv3t1ktbjn8m4lk5', '216.73.217.172', '1790315121', '1790315121', '/index.php?XTCsid=25e3a9d33bac206ca2799e0bee35f2b1&cat=c9_Tabledeko.html')

[XT SQL Error]