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', 'qktsb1f8nf6715pkncfns6qev1', '216.73.216.147', '1751585840', '1751585840', '/shop_content.php?coID=7&XTCsid=33509f1bee4ee2cbb673a74e5faae0d4')

[XT SQL Error]