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', 'rj2ghikj85sqf7adf0im29cug7', '216.73.216.147', '1751743302', '1751743302', '/shop_content.php?coID=7&XTCsid=6c2468ca28c6c182aaed37353d32ae32')

[XT SQL Error]