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', '9h6cj8ht9jhen0q5d35vadlvv6', '216.73.216.110', '1752060354', '1752060354', '/shop_content.php?coID=8&XTCsid=363052f8eb28c495db1ddeca225278d6')

[XT SQL Error]