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', 'a9bit2avmklq10g742jdtaevn4', '3.15.2.77', '1738993440', '1738993440', '/index.php?XTCsid=3ea3bnp0vmbqarg8bfequsbfv5&cat=c1051_Gardena-Werkzeug-Akku.html')

[XT SQL Error]