We need to execute some SQL statements which are constructed on run time - hence cannot have a HBM or Class corresponding to them.

Can someone please tell what is the method to execute such statements using NHibernate and C#.

Have a look here http://www.hibernate.org/hib_docs/nhibernate/1.2/reference/en/html/querysql.html

Also note that there is nothing about IQuery and ICriteria that prevents runtime query generation, in fact IMHO that is where ICriteria excels.

As per your reply, we used AddScalar to run the query. Thanks for the help !