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', '3k5d4dj4jkskcur1mglm72amh5', '18.234.88.196', '1558466640', '1558466640', '/lkw_plane_tasche_lkw_plane/product_info.php/info/p141')

[XT SQL Error]