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', 'b968ia9bckv1cb3mbtsdbng1i5', '216.73.216.220', '1764040077', '1764040077', '/shop_content.php?XTCsid=3f98699a7205aa16d7f8014dc7c0d34a&coID=7')

[XT SQL Error]