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', 'm6kc6m41t5u0l30rpseg2vis70', '216.73.216.167', '1762558115', '1762558115', '/index.php?XTCsid=72205775904d1a5c41b590dd7b5ff1d6&cat=c4_Beer-Mugs.html')

[XT SQL Error]