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', 'ioqp5tvi0u3f3g262u1oud4hp2', '216.73.216.7', '1758230889', '1758230889', '/index.php?XTCsid=38f09672db884903e3803adf9d076819&cat=c4_Beer-Mugs.html')

[XT SQL Error]