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', 'e6mblfgphtf51dh6vf7iaugv77', '18.234.88.196', '1558467574', '1558467574', '/messenger_bag_tote_bag_canvas_cover/shop_content.php/coID/7/content/Kontakt')

[XT SQL Error]