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', 'akm84e8jqs7uooci023cm4vdl3', '216.73.216.147', '1751743691', '1751743691', '/index.php?XTCsid=1d5dd97ce421ec9dee05990fab78bd20')

[XT SQL Error]