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', '7lpmfv6jn1spvcoiccefjlo3q3', '216.73.217.62', '1783164483', '1783164483', '/index.php?XTCsid=7c604026da355cfd6a094c68b431572d&cat=c6_Foodstuffs.html')

[XT SQL Error]