Database Reference
In-Depth Information
Chapter 14
Reporting with MDX Queries
But for me, it was a code I myself had invented! Yet I could not read it.
—Erno Rubik
Multidimensional Expressions (MDX) is a Microsoft-owned specification, not an open standard language. But,
it has been adopted by many vendors and is considered an industry standard for querying and manipulating
multidimensional data for SSAS.
If you are working with OLAP cubes, you will likely be working with MDX at some point. While you do not
have to be an expert in MDX to work with SSAS cubes, acquiring a more in-depth understanding of the language
is helpful in a number of ways. For example, calculated members, KPIs, and security structures within SSAS
require MDX expressions. And while many client applications can work to create MDX code for you, you may find
yourself troubleshooting to find out why the MDX code you are using is not returning the data you want. If you
are unable to read MDX, you will not be able to manage troubleshooting problems.
Superficially, MDX is similar to the SQL language; however, MDX also has many differences. In this chapter,
we explore these similarities and differences, and show you how to read and create MDX queries.
Key Concepts and Terms
You do not have to know everything about OLAP cubes to begin programming in MDX, but there are a few key
concepts and terms that you need to know before you begin. Let's begin by reviewing some of them.
Consider a typical date dimension hierarchy, as shown in Figure
14-1
. The dimension hierarchy is made up
of levels such as year, month, and quarter. The dimension attributes are made up of members, such as 1992, 1993,
and 1994.
