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', 'bhoahjdt8aj8i1i4jihi659826', '216.73.216.113', '1775391203', '1775391203', '/shop_content.php?XTCsid=d3f81aac1b90a5822d8663a3af39931e&coID=7')

[XT SQL Error]