1366 - Incorrect integer value: '' for column `mapshopatlogis`.`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', '744f298137c70fd017061f0a9b73068c', '216.73.216.121', '1751952124', '1751952124', '/index.php/language/en')

[XT SQL Error]