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', 'ub0dene7vufci61g01q7qs68t1', '216.73.216.7', '1758242111', '1758242111', '/index.php?XTCsid=d6a8bfd6f6ba5ba5c5448fc18660454f&cat=c13_Accessoires.html')

[XT SQL Error]