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', 'fa6ndm000ho0svhokf17v7n9k1', '216.73.217.128', '1790013968', '1790013968', '/product_info.php?XTCsid=1455d70b156c4853db961f68b595bbe7&info=p2_Bavarian-Pennant-Chain.html')

[XT SQL Error]