MashQL is a semantic data mashup language. The idea of MashQL is to allow people to query, mash up, and pipeline RDF data intuitively. In the background MashQL queries are automatically translated into and executed as SPARQL queries. The novelty of MashQL is that it allows one to query (and navigate) an RDF graph without any prior knowledge about its schema, vocabulary, structure or technical details; as well as it supports query pipelines as a built-in concept.
MashQL is also called as a query-by-diagram language where users create mashups in a graphical manner while the queries are generated in the background. This is different from more developer oriented approaches such as extensible Javascript for instance.
References
MashQL Wikipedia(Text) CC BY-SA