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', 'u4uq02mqklvjmcj37qtvec1t61', '216.73.216.162', '1764344878', '1764344878', '/product_info.php?info=p552_800468-Futterstampfer--Ruebenstoesser--S-foermig.html')

[XT SQL Error]