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', '0vd54mj81n9iv43n4p79f7qtp4', '216.73.216.205', '1780363819', '1780363819', '/product_info.php?XTCsid=f6e58886be8011b1d9a8e232c116cb7a&info=p15_25-balloons.html')

[XT SQL Error]