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', 't2qbk72oea59in2s6no6cb01i7', '3.135.221.122', '1739000700', '1739000700', '/index.php?XTCsid=o64jeukdqdg9btq7j80htrr7d3&cat=c722_Funk-Kopfh--rer-Akku.html')

[XT SQL Error]