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', 'vrfvlgevqgeir3bl40h9j8f2n4', '216.73.216.131', '1771028755', '1771028755', '/product_info.php?XTCsid=3e3fcef0642c69bbf707de3c0bc1cf9c&info=p7_Garland-13-feet.html')

[XT SQL Error]