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', 'n2l5fe0vbrqu1epejedhh2pse3', '216.73.216.147', '1751596077', '1751596077', '/index.php?cat=c8_Disposable-tableware.html&XTCsid=fba53dc6b549a2b9cad4403a2504e4ed')

[XT SQL Error]