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', 'q8jl4c56fil1cb8rf33gqhskp3', '13.59.90.172', '1746790049', '1746790049', '/xtshop/product_info.php?info=p773_.html')

[XT SQL Error]