1366 - Incorrect integer value: '' for column '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', 'f325cd973ea04bb67a25e25fa1935c40', '52.14.168.56', '1714004697', '1714004697', '/shop_content.php/coID/3/content/Unsere-AGB-s')

[XT SQL Error]