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', '16fgj7a5caah0k1r6r0lt8vl45', '216.73.216.80', '1751323860', '1751323860', '/index.php?XTCsid=0030a67ff458d3886f5d2b053ac68d0c')

[XT SQL Error]