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', 'i8qn89n6p3f9r0tpkk9krcb0s4', '216.73.217.128', '1790087035', '1790087035', '/product_info.php?XTCsid=ca28ab8f46bb6e791b42fe9b92719761&info=p17_20-Tissue-Napkins.html')

[XT SQL Error]