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', 'lubu90g5g92n1cgcqq80oj26u7', '216.73.217.152', '1790935589', '1790935589', '/index.php?XTCsid=a6fef95dcbdcf765a3c6baf6e1fe0e25&cat=c12_Music.html')

[XT SQL Error]