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', 'd43d0c5d63d2c6d7a2797e927d76b520', '216.73.216.190', '1776277372', '1776277372', '/shop/product_info.php?info=p4_.html')

[XT SQL Error]