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', 't53laoe5aemnvv0j571uk6b9h3', '216.73.216.167', '1762634713', '1762634713', '/index.php?XTCsid=0832187515ca706758d8e1ce01e34faf&cat=c5_Crockery.html')

[XT SQL Error]