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', '9qc9n8pbiao1b6v6tgml2bde64', '216.73.216.147', '1751967237', '1751967237', '/index.php?cat=c5_Crockery.html&XTCsid=7f3d063595fd0cf7dd24ecea4b1409d6')

[XT SQL Error]