Denodo provides the Virtual Query Language (VQL) to perform queries and manage the data from the sources. That language is a SQL-like language highly compatible with SQL 92 ANSI standard. Hence, all the aggregations, selections etc can be performed as in a traditional SQL database.
In this article of the Denodo Knowlegde Base, (https://community.denodo.com/kb/view/document/VDP%20Conformance%20with%20Standard%20SQL?category=VQL) we explain the conformance with the SQL 92 ANSI standard.
Hope this helps!