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', 'rajb47v27g5p6kgu1t4hglvkv1', '216.73.216.110', '1752056923', '1752056923', '/index.php?language=en&cat=c6_Foodstuffs.html&XTCsid=6c2468ca28c6c182aaed37353d32ae32')

[XT SQL Error]