MDX in Analysis Services: Mastering Time: Change across Periods
May 24, 2004
About the Series ...
This is the fifteenth tutorial article of the series, MDX in Analysis Services. The series is designed to provide hands-on application of the fundamentals of MDX from the perspective of MS SQL Server 2000 Analysis Services ("MSAS"); our primary focus is the manipulation of multidimensional data sources, using MDX expressions, in a variety of scenarios designed to meet real-world business intelligence needs.
For more information on the series, as well as the hardware / software requirements to prepare for the tutorials we will undertake, please see the first lesson of this series: MDX Concepts and Navigation.
Note: At the time of writing, Service Pack 3 updates are assumed for MSSQL Server 2000, MSSQL Server 2000 Analysis Services, and the related Books Online and Samples. The screen shots that appear in this article were taken from a Windows 2003 Server, and may appear somewhat different from coinciding views in other operating systems.
In our last tutorial, Introducing DISTINCT COUNT, we introduced the concept of distinct counts, discussing why they are often a requirement in our analysis efforts and those of the information consumers whom we support. In our introduction and throughout our examination of the MDX syntax we assembled to achieve our illustrative objectives, we highlighted the challenges that accompany the use of distinct counts. We performed practice exercises, to illustrate solutions for hypothetical business needs that called upon the use of distinct count capability, obtaining exposure to the options afforded us by the MSAS user interface, as well the MDX syntax involved with using the alternative solutions that we proposed.
In this article and others subsequent to it, we will focus on time considerations in our MDX queries, and how we can successfully report change over time, as well as to accumulate those changes to present the precise snapshots, trends and other time-based metrics so dearly appreciated in business. We will briefly discuss common needs with regard to relative time, and then undertake a multi-step practical exercise, built around a hypothetical business need, to illustrate a potential solution for that need.