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', '4mki3sthl9qn1ohed6qe5j27l5', '216.73.216.176', '1762255492', '1762255492', '/index.php?XTCsid=68ade1b37223d7a85541797e5ace892d')

[XT SQL Error]