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', 'jkq51iuet2pqa9o2nc6f226hm2', '54.162.109.90', '1495804389', '1495804389', '/shop_content.php?coID=9&watch=1098')

[XT SQL Error]