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', 'eut2q9n85nn0l11irmgjve3cc2', '107.22.127.78', '1493220873', '1493220873', '/password_double_opt.php')

[XT SQL Error]