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', 'p72gfafbbr4o9kds1s3s5m6qt4', '216.73.216.82', '1752527452', '1752527452', '/popup_content.php?coID=1&XTCsid=d3f81aac1b90a5822d8663a3af39931e')

[XT SQL Error]