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', 'lpr3skdpbm05bm0i8jl6a5ef71', '216.73.216.181', '1758230367', '1758230367', '/xtshop/product_info.php?info=p1015_.html')

[XT SQL Error]