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', 'n2c6g2d1d5bc2fpiv8rod7rea7', '216.73.217.68', '1789334254', '1789334254', '/product_info.php?XTCsid=4299a8bbf7f56cb5a06703b866244eb3&info=p2_Bavarian-Pennant-Chain.html')

[XT SQL Error]