Originally Posted by mike

No Sarma you cannot update items in your Salesforce instance performing SQL statements such as this. The best advice that I could give you is to create scripts that will download your data from Salesforce into local DB tables (I have done this for Oracle and MySQL), manipulate the data locally then use select statements to create insert, update, and upsert script back into your org's instance of salesforce. I have examples of how to create backup scripts on this site

Hope that helps

~Mike