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', '5qjfn1qspm7qj0ok3gt3vq1gl1', '54.162.109.90', '1495804275', '1495804275', '/shop_content.php?coID=9&watch=1066')

[XT SQL Error]