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', 'l2803ikoqv2sh7fs8fo0j9cg46', '216.73.216.80', '1751321300', '1751321300', '/index.php?XTCsid=1edacbd1b1da241cee49f7b785c52673')

[XT SQL Error]