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', 'm5sdghih0vm6q9uoecbcgoeub6', '216.73.216.82', '1752527452', '1752527452', '/index.php?cat=c2_Decoration.html&XTCsid=2fab07f7a09b13e4ee5c8e548c6bf380')

[XT SQL Error]