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', 'vvlqoimlctju8c1arkpm6950k1', '3.85.92.139', '1561473527', '1561473527', '/product_info.php/info/p9_Tec-Gummi-Flossen-XXXL.html')

[XT SQL Error]