1366 - Incorrect integer value: '' for column `CP_as15`.`whos_online`.`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', '1jgf28blv6ltsjdl1vdtcmn2o7', '3.18.112.171', '1738997751', '1738997751', '/index.php?XTCsid=nmu1l7bj1113ksvu525rsptc72&cat=c638_Blei-Akkus.html')

[XT SQL Error]