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', 'bq86nhh8p5j4aujj2d6e8pfel7', '216.73.216.122', '1767872592', '1767872592', '/index.php?XTCsid=7721da20a623cbf55c11923452088e5a')

[XT SQL Error]