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', '12gjd3g8o61p5o10qktt2e7mn4', '216.73.216.127', '1752881864', '1752881864', '/index.php?cat=c2_Decoration.html&XTCsid=7c604026da355cfd6a094c68b431572d')

[XT SQL Error]