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', 'bi2g1vopmhrbj575vsmv1p94p7', '216.73.216.244', '1752208450', '1752208450', '/products_new.php?XTCsid=72205775904d1a5c41b590dd7b5ff1d6')

[XT SQL Error]