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', 'p2t7k05q1hctjs2b7eic8m83k1', '18.97.14.80', '1745118766', '1745118766', '/xtshop/product_info.php?info=p1096_.html')

[XT SQL Error]