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', 'ao54fmufrt8dthb0t1k8ji3vb6', '216.73.216.7', '1758256664', '1758256664', '/product_info.php?XTCsid=80c3e9fc87b53cb0d288d19ef4e9b63c&info=p22_Plastic-tablecloth.html')

[XT SQL Error]