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', 't5ehtr3q4nnk8ilcqjhse7jef5', '216.73.216.145', '1778151031', '1778151031', '/index.php?XTCsid=fae679bbce3acf80896a0577fc4b4b9a&cat=c6_Foodstuffs.html')

[XT SQL Error]