1366 - Incorrect integer value: '' for column `agentur`.`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', '561fgevp59etha51bdniphi941', '18.207.106.142', '1600706176', '1600706176', '/index.php?cat=c139_Uschi-Obermaier-Buchvorstellung.html&XTCsid=2d4qg7ftupcpr3opjmmv969b12')

[XT SQL Error]