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', '0ngfognjdto5j108kntolh8km4', '18.218.36.242', '1746773767', '1746773767', '/xtshop/product_info.php?info=p402_.html')

[XT SQL Error]