MDX or "MultiDimensional Expressions" is not only a specialized query language for querying and manipulating data stored in Analysis Services OLAP cubes. It is also a calculation language with syntax similar to Excel formulas. It has been embraced by a wide majority of OLAP vendors and has become the standard for interrogating OLAP systems.
MDX queries and expressions in SQL Server Analysis Services (SSAS) can be used to :
- Return data to a client application (like Reporting Services) from an SSAS cube
- Format query results
- Perform cube design tasks like defining calculated members, named sets and KPI's
- Perform administrative tasks like dimension and cell security