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', '56535pvn889bhtraolr7j1ncg6', '3.138.124.40', '1738999244', '1738999244', '/index.php?XTCsid=3o9rajic4fkoo3bb243kehab14&cat=c895_Display-Schutzfolien-f--r-Handys.html')

[XT SQL Error]