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', 'rn31kf8c5amda6qlgkqrd0h372', '216.73.216.128', '1771456481', '1771456481', '/product_info.php?info=p32_800529-Ruebenmuehle-mit-Fu-gestell.html')

[XT SQL Error]