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', 'b90r9f8gh4ivi4h6q4r7rqvhc5', '216.73.216.139', '1770252297', '1770252297', '/product_info.php?XTCsid=38f09672db884903e3803adf9d076819&info=p16_Octoberfest-CD.html')

[XT SQL Error]