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', 'b8vjhlkabqe50ra5emfj0tui23', '216.73.216.130', '1761186923', '1761186923', '/index.php?XTCsid=1d5dd97ce421ec9dee05990fab78bd20')

[XT SQL Error]