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', '3b5a0d0092afedbcf659c239aff4cf58', '216.73.217.165', '1780980828', '1780980828', '/shop/product_info.php?info=p84_.html')

[XT SQL Error]