Graphs have become an ubiquitous type of data, increasing the desire and need to perform analytics on graph data.
In this article, we review the fundamental concepts that form the common basis of most declarative graph querying languages. The article conveys a general understanding of these concepts which will help the reader to learn a specific graph query language, rotate between graph query language, and work with graph database system in general. We also provide examples in query languages such as Cypher and SPARQL that illustrate how the discussed concept manifest in specific graph query languages. Further, we take a look at how these concepts of declarative graph query languages can be extended towards declarative multidimensional queries, to facilitate the most fundamental form of analytics on graphs in graph database systems. This helps the reader to develop a fundamental understanding of aggregating graph structure for analytical purposes.