1366 - Incorrect integer value: '' for column `hbl_shop`.`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', 'c8tugqm3u1k46ntidddccsv8m7', '216.73.216.47', '1758022142', '1758022142', '/product_info.php?info=p94_Ersatz-Walze-fuer-Tisch-Ruebenmuehle--extrafein-.html')

[XT SQL Error]