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', 'kcofrmoqqu8d7rg73av0684745', '216.73.216.113', '1752883988', '1752883988', '/product_info.php?info=p12_33-feet-crape-paper.html&XTCsid=a8f768c639dfd62c2d6d3cd7ed21b720')

[XT SQL Error]