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', 'm18ljh8vha0de2nl5q3pj37i42', '216.73.216.87', '1769309338', '1769309338', '/index.php?XTCsid=6c2468ca28c6c182aaed37353d32ae32&cat=c12_Music.html')

[XT SQL Error]