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', 't6t2k9tbj4foj9ogb8t7p11e82', '216.73.216.170', '1792750035', '1792750035', '/index.php?XTCsid=4635a65037080db684b109117d2fc14c')

[XT SQL Error]