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', 'is76jhhb77kmpcppu4efeqr5f1', '216.73.216.110', '1752057018', '1752057018', '/index.php?cat=c8_Disposable-tableware.html&XTCsid=0308d34f52db367f9a7068f51bec2a23')

[XT SQL Error]