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', 'lh6hul0ov7ud2e73pkrttfj1a1', '3.138.67.47', '1738993739', '1738993739', '/index.php?XTCsid=3ea3bnp0vmbqarg8bfequsbfv5&cat=c174_Fein-Werkzeug-Akku.html')

[XT SQL Error]