*Author Bill Pearson
continues his *MDX Essentials* Series
with a discussion of three basic operators: Braces, Comma, and **Colon**.
After a brief review of each, we examine the syntax involved in putting it into
action, and the practical use of the operator in helping us to achieve our
query objectives.*

### About the Series ...

This is the third article of the
series, **
MDX Essentials**.
The primary focus of this series is an introduction to the MDX language. 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 needed for getting the most out of the
lessons included, please see the first article, *MDX
at First Glance: Introduction to MDX Essentials**.*

### What We Accomplished in our Last Article

In the **second
article of the series**,
we introduced the MDX data model, together with its
most basic components, **tuples**, **axes**, and **sets**. We focused
on the composition and common uses of tuples, axes and sets, and provided
hands-on exposure to these building blocks. After discussing each of the three
components, we
emphasized rules of syntax that related to each, providing a foundation to
build upon throughout the rest of the series. Finally, we worked practice
exercises to demonstrate tangible results, and to reinforce our discussions
with examples.

In
this lesson, ** MDX
Operators: The Basics**, we will introduce additional ways
to construct tuples and sets, taking up first the most basic of the components
involved. The operators we explore in this lesson will include

**curled braces**"

**{}**",

**commas**"

**,**" and

**colons**"

**:**". With each of the operators, we will illustrate the uses and options that are available to us in constructing basic MDX queries.

### Introduction to Basic Operators

In this article, we will introduce basic components involved in the building of tuples and sets. We will focus on the composition of these important building blocks, and provide hands-on exposure to their use in simple expressions that we will run to view their output. Rules of syntax will be emphasized, the aggregate body of which will provide a basis for more complex query building as we progress through the series.

This lesson will include:

- A brief discussion of
**curled braces**"**{}**",**commas**"**,**" and**colons**"**:**"; - A examination of the
**MDX query results we obtain**in examples that use the operators under consideration.

Let's begin by discussing the most common of the MDX operators, and some of the ways that we can call upon them in the development of expressions that we can use in standalone fashion, or that we might use in more sophisticated expressions or queries, to achieve our ends.

### Basic Operators: Curled Braces, Commas and Colons

We previewed the use of curled
braces and commas in our last session, within our overview of sets, and in
other passages of the lesson. Curled (or "curly," depending upon whom you ask)
braces ** must** be used in some situations, and simply

**be used in others. We will touch on these, as well as upon the use of curled braces to set apart set expressions consistently, to make learning MDX easier. As we stated in our last section, MDX is similar to other programming languages in its uses of various operators; one of those uses is to identify sets. Among these operators are the colon and comma (used as separators between members within sets), which, along with curled braces, will form the subjects of this lesson.**

*can*