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', 'teav4195ig77ov9v844gs65ac0', '216.73.216.28', '1765099924', '1765099924', '/index.php?XTCsid=734cd4ccfdd28635aaee5aea39e89c84')

[XT SQL Error]