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', '5faee0iv8vkg1p9hso16jggt84', '216.73.216.141', '1751424020', '1751424020', '/product_info.php?info=p2_Bavarian-Pennant-Chain.html&XTCsid=0308d34f52db367f9a7068f51bec2a23')

[XT SQL Error]