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', '3aic1516bk2f7gqjtrf273pmh1', '216.73.216.130', '1761181631', '1761181631', '/product_info.php?XTCsid=38f09672db884903e3803adf9d076819&info=p9_Paper-Lantern.html')

[XT SQL Error]