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', 't100k2apgjvu9p6bpmu5r0vcq4', '216.73.216.28', '1765405586', '1765405586', '/products_new.php?XTCsid=72205775904d1a5c41b590dd7b5ff1d6&language=en')

[XT SQL Error]