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', '4thnvlhf699soo3e6p4a0il3c1', '216.73.216.49', '1752610143', '1752610143', '/xtshop/product_info.php?info=p1016_.html')

[XT SQL Error]