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', 'h4t6titi4j475bqo2rh56snpg1', '216.73.216.116', '1782692230', '1782692230', '/product_info.php?XTCsid=f6e58886be8011b1d9a8e232c116cb7a&info=p12_33-feet-crape-paper.html')

[XT SQL Error]