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', 'p873qelvdkj8201eg5ht0n8924', '216.73.217.116', '1786441411', '1786441411', '/index.php?XTCsid=c60d173e05a16d5feea88bc4b1883fc9')

[XT SQL Error]