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', '0g00oaaq21pdpor2f2armfgd74', '216.73.216.118', '1761450960', '1761450960', '/product_info.php?XTCsid=f6e58886be8011b1d9a8e232c116cb7a&info=p21_Paper-tablecloth-10-meters.html')

[XT SQL Error]