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', '0bk0g18dqsfofi9mqohrb3cgi3', '216.73.216.147', '1751746198', '1751746198', '/index.php?language=de&cat=c13_Accessoires.html&XTCsid=705a3b68bece48fd9b67e5e30d623e8e')

[XT SQL Error]