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', '487stj50d5oisi5vr50rl7js31', '216.73.217.80', '1790188100', '1790188100', '/product_info.php?XTCsid=38717c4dd62e88001622b2c7b8b8372a&info=p2_Bavarian-Pennant-Chain.html')

[XT SQL Error]