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', 'vjknmtr6qq3iuiu0gqnuo9d2f6', '216.73.216.185', '1752882547', '1752882547', '/index.php?cat=c2_Decoration.html&XTCsid=f6e58886be8011b1d9a8e232c116cb7a')

[XT SQL Error]