In this chapter and the next one, we turn our attention to Multidimensional Expressions (MDX) programming. MDX is the query language for OLAP data warehouses (cubes). Generally speaking, MDX is to OLAP databases as Transact-SQL is to Microsoft SQL Server relational databases. OLAP applications use MDX to retrieve data from OLAP cubes and to create stored and reusable calculations or result sets. MDX queries usually comprise several items:
Language statements (for example, SELECT, FROM, and WHERE)
OLAP dimensions (a geography, product, or date hierarchy)
Measures (for example, dollar sales or cost of goods)
Other MDX functions (Sum, Avg, Filter, Rank, and ParallelPeriod)
Sets (ordered collections of members)
We take a ...