MDX Essentials: Basic Set Functions: The TopCount() Function, Part I

About the Series …

This article is a member of the series, MDX Essentials.
The series is designed to provide hands-on application of the fundamentals of
the Multidimensional Expressions (MDX) language, with each tutorial
progressively adding features designed to meet specific real-world needs.

For more information about the series in general, as well as
the software and systems requirements for getting the most out of the lessons
included, please see my first article, MDX at
First Glance: Introduction to MDX Essentials
.

Note: Current updates are assumed for MSSQL
Server
, MSSQL Server Analysis Services, and the related Books
Online
and Samples.

Overview

In this article, we will examine the TopCount() function,
whose highest value lies in its capability to enable us to isolate best
performers from among hundreds or thousands of fellow members. This ranking
capability is critical in data analysis and decision support scenarios: In many
business situations, we seek to report upon "best performers" for
various reasons. TopCount() facilitates our doing so, allowing us to
sort on a numeric value expression that we can provide. We can tell the
function how many "top" members we wish to retrieve (say, the "top
ten," or the "top twenty"), for a "custom-fit" approach,
that matches our needs precisely.

In
this article, we will introduce and overview the TopCount() function. We
will first comment upon the general operation of TopCount(), and then we
will:

  • Examine the syntax surrounding the function;

  • Undertake illustrative examples of the rudimentary uses of the
    function in practice exercises;

  • Briefly discuss the results datasets we obtain in the practice
    examples.
William Pearson
William Pearson
Bill has been working with computers since before becoming a "big eight" CPA, after which he carried his growing information systems knowledge into management accounting, internal auditing, and various capacities of controllership. Bill entered the world of databases and financial systems when he became a consultant for CODA-Financials, a U.K. - based software company that hired only CPA's as application consultants to implement and maintain its integrated financial database - one of the most conceptually powerful, even in his current assessment, to have emerged. At CODA Bill deployed financial databases and business intelligence systems for many global clients. Working with SQL Server, Oracle, Sybase and Informix, and focusing on MSSQL Server, Bill created Island Technologies Inc. in 1997, and has developed a large and diverse customer base over the years since. Bill's background as a CPA, Internal Auditor and Management Accountant enable him to provide value to clients as a liaison between Accounting / Finance and Information Services. Moreover, as a Certified Information Technology Professional (CITP) - a Certified Public Accountant recognized for his or her unique ability to provide business insight by leveraging knowledge of information relationships and supporting technologies - Bill offers his clients the CPA's perspective and ability to understand the complicated business implications and risks associated with technology. From this perspective, he helps them to effectively manage information while ensuring the data's reliability, security, accessibility and relevance. Bill has implemented enterprise business intelligence systems over the years for many Fortune 500 companies, focusing his practice (since the advent of MSSQL Server 2000) upon the integrated Microsoft business intelligence solution. He leverages his years of experience with other enterprise OLAP and reporting applications (Cognos, Business Objects, Crystal, and others) in regular conversions of these once-dominant applications to the Microsoft BI stack. Bill believes it is easier to teach technical skills to people with non-technical training than vice-versa, and he constantly seeks ways to graft new technology into the Accounting and Finance arenas. Bill was awarded Microsoft SQL Server MVP in 2009. Hobbies include advanced literature studies and occasional lectures, with recent concentration upon the works of William Faulkner, Henry James, Marcel Proust, James Joyce, Honoré de Balzac, and Charles Dickens. Other long-time interests have included the exploration of generative music sourced from database architecture.

Latest Articles