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', 'dhtga6ntv4mvr7qpa194tlfm82', '216.73.216.167', '1762471251', '1762471251', '/index.php?XTCsid=23380c0ea5ceb30ea6ad18aac0802b89')

[XT SQL Error]