RDF is the leading data model for the Semantic Web, and dedicated query languages such as SPARQL 1.1, featuring in particular aggregation, allow extracting information from RDF graphs. A framework for analytical processing of RDF data was introduced in [1], where analytical schemas and analytical queries (cubes) are fully re-designed for heterogeneous, semantic-rich RDF graphs. In this novel analytical setting, we consider the following optimization problem: how to reuse the materialized result of a given analytical query (cube) in order to compute the answer to another analytical query obtained through a typical OLAP operation. We provide view-based rewriting algorithms for these query transformations, and demonstrate experimentally their practical interest.