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', 'sojnorm9kk8loe09873ath3m36', '216.73.216.197', '1751514236', '1751514236', '/index.php?cat=c8_Disposable-tableware.html&XTCsid=1ce6d0a6925740e42ccf6986944a240a')

[XT SQL Error]