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', '5ghjvl4k0or2sn9uitt0prt8d3', '216.73.216.178', '1768959993', '1768959993', '/index.php?XTCsid=3f98699a7205aa16d7f8014dc7c0d34a&cat=c13_Accessoires.html')

[XT SQL Error]