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', 'oqb3bpfqrjrve60ctsmgl6vle3', '216.73.216.127', '1752882165', '1752882165', '/index.php?cat=c5_Crockery.html&XTCsid=38f09672db884903e3803adf9d076819')

[XT SQL Error]