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', '9f7f877c377b0cc4758c28008ab1b482', '216.73.216.190', '1776277369', '1776277369', '/shop/product_info.php?info=p7_.html')

[XT SQL Error]