Hello All,
Could someone please explain or point to an explanation of
algorithms used to convert HQL to SQL ?

Thank you

Boris

Its best to reference the source. It is difficult to explain it here (and some of the deep internals I am not that familar with).
In anycase, since HQL is based on SQL with the ORM twist alot of the HQL is passed directly without modification to the SQL engine.
Where most of the work needs to be done is in the select clause where not only the class property may need to be converted but the type of the expression has to be determined. In the case of the select functions (that may also be nested) its possible type conversions may need to occur.
Check the net.sf.hibernate.hql.* for the parser classes. Conversions etc occur then its time to load it - check out the loader classes in net.sf.hibernate.loader.* (in particular Loader.java). Lastly have a look through the net.sf.hibernate.persister.* classes for getting close to the metal.

Thanks for reply David, and sorry for crossposting,
i just was not sure which forum was the best.

And yes, source is the best source :) but not the easiest.
I was hoping that someone wrote an overview of the approach.

Anyone ???

Best,
Boris