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', 'mehnf2fb1g9e51bgc2h2o5m885', '216.73.217.60', '1780223210', '1780223210', '/index.php?XTCsid=5452c15f57f0ea9ce022f9dc9cfaa045&cat=c12_Music.html')

[XT SQL Error]