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', '4fogcdhdve68q0p4ah5u46r7f0', '3.145.149.120', '1746770567', '1746770567', '/xtshop/index.php?cat=c23_.html')

[XT SQL Error]