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', 'r259t8p829fitaeb918vk6sbc5', '18.191.235.161', '1746789624', '1746789624', '/xtshop/product_info.php?info=p1090_.html')

[XT SQL Error]