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', 'imnktd8t2cosln2siplap4hgg4', '216.73.216.82', '1752528657', '1752528657', '/index.php?XTCsid=3eeb6feb9f3fdb095dcf133e6414bb24')

[XT SQL Error]