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', 'dun4f8cqju3b848g64srjoi6c2', '216.73.216.147', '1751764467', '1751764467', '/product_info.php?info=p12_33-feet-crape-paper.html&XTCsid=33509f1bee4ee2cbb673a74e5faae0d4')

[XT SQL Error]