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', 'nqcd0iq3rt3i5t04coefjkih16', '216.73.216.9', '1758131782', '1758131782', '/product_info.php?XTCsid=38f09672db884903e3803adf9d076819&info=p11_Fan-for-decorations.html')

[XT SQL Error]