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', 'k54jeq1hgb3b07as64q3agi7q4', '216.73.216.141', '1751426011', '1751426011', '/index.php?XTCsid=c9522ec8d7d3242bfbea3f87266d3e01')

[XT SQL Error]