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', '6c57d307623f6148f2d4d449787ffb99', '3.17.166.43', '1746150331', '1746150331', '/shop/product_info.php?info=p159_Anders-Kochen-von-Soeren-Anders.html')

[XT SQL Error]