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', 'f6ja1buhjrpu2e35qr44piel53', '216.73.216.165', '1752394450', '1752394450', '/shop_content.php?coID=2&XTCsid=c0f978c48adcbf133ea0f5b346c18fa2')

[XT SQL Error]