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', 't2tgluesra3csfan19g9taj5r4', '3.85.92.139', '1561470741', '1561470741', '/product_info.php/info/p14_P-weight---Backplate-Gewicht---2-8-kg.html')

[XT SQL Error]