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', 'lhdjb5fop2sftfk2j7n7g1p6p2', '216.73.216.165', '1752304026', '1752304026', '/product_info.php?info=p11_Fan-for-decorations.html&XTCsid=1455d70b156c4853db961f68b595bbe7')

[XT SQL Error]