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', 'nee8vq664njgarkbq61oqo7f31', '216.73.216.9', '1758200152', '1758200152', '/index.php?XTCsid=679e5364f8ebcbd98062f6d07b727e6d&cat=c13_Accessoires.html')

[XT SQL Error]