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', 'r4i23q90cd431e6jb4ed89jrf5', '216.73.216.147', '1751760148', '1751760148', '/product_info.php?info=p6_100-Paper-Plates.html&XTCsid=72205775904d1a5c41b590dd7b5ff1d6')

[XT SQL Error]