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', 'ajitm4i3cc0h006vlbh4ieit87', '216.73.217.172', '1790334127', '1790334127', '/index.php?XTCsid=5f051c452f1f75cd071b180063acc15b')

[XT SQL Error]