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', 'vf9qqautb3llufjjnrr51skif1', '18.234.88.196', '1558467480', '1558467480', '/lkw_plane_tasche_lkw_plane/product_info.php/info/p108_Tasche-30-38-10-gelb-braun-mit-B-gen-in-rot-und-orange.html')

[XT SQL Error]