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', 'ast6lj8oh8kphvh26hm5e26mv3', '3.148.196.9', '1746771094', '1746771094', '/xtshop/product_info.php?info=p373_.html')

[XT SQL Error]