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', 'vpm6ua7vbcjoijk72ql9ovv375', '216.73.217.78', '1791215800', '1791215800', '/shop_content.php?XTCsid=1455d70b156c4853db961f68b595bbe7&coID=7')

[XT SQL Error]