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', '7d25dt7g7kuq7innp7i2dsviu7', '216.73.216.150', '1786170380', '1786170380', '/index.php?XTCsid=7b707b7fd087f4e89537b6e7947fb886')

[XT SQL Error]