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', '1d5hd1jsvi9g6c9a40it6tbo04', '216.73.216.139', '1770540255', '1770540255', '/product_info.php?XTCsid=c407ede434192d8d024c7c2f06b2be8c&info=p11_Fan-for-decorations.html')

[XT SQL Error]