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', 'gq9ioetq431s6e79nk8emhh8m3', '18.217.244.16', '1746774876', '1746774876', '/xtshop/product_info.php?info=p557_.html')

[XT SQL Error]