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', 'bmp1a59vi5990j5ptcr9na1de6', '216.73.216.176', '1762340228', '1762340228', '/shop_content.php?XTCsid=38f09672db884903e3803adf9d076819&coID=1')

[XT SQL Error]