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', '85b2epr150ft0espmr8pb86bj2', '216.73.216.167', '1762465750', '1762465750', '/product_info.php?XTCsid=38f09672db884903e3803adf9d076819&info=p15_25-balloons.html')

[XT SQL Error]