Microsoft SQL Server 2008 MDX Step By Step

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Introduction to MDX

Microsoft SQL Server 2008 MDX is a powerful data-access query language used for SQL Server Analysis Services. It is a fundamental tool for delivering high-performance business intelligence solutions. In this step-by-step guide, we will teach you the Multidimensional Expressions (MDX) query language, one step at a time. By the end of this tutorial, you will have built the core techniques for using MDX with Analysis Services.

What is MDX?

MDX is a query language used to extract data from a multidimensional database. It is a powerful tool for analyzing and reporting data in a business intelligence environment. MDX is used to construct and execute queries that retrieve data from a cube, which is a multidimensional database that stores data in a structured format.

Why Use MDX?

MDX is a powerful tool for delivering high-performance business intelligence solutions. It allows you to:

  • Construct and execute MDX queries to retrieve data from a cube
  • Work with tuples, sets, and expressions to analyze and report data
  • Build complex sets to retrieve the exact data users need

Step 1: Constructing and Executing MDX Queries

To start using MDX, you need to construct and execute MDX queries. An MDX query is a statement that retrieves data from a cube. The basic syntax of an MDX query is as follows:

SELECT <axis> ON COLUMNS FROM <cube>

Where:

  • <axis> is the axis of the cube that you want to retrieve data from
  • <cube> is the name of the cube that you want to retrieve data from

For example, to retrieve data from the Sales axis of the SalesCube cube, you would use the following MDX query:

SELECT [Sales] ON COLUMNS FROM [SalesCube]

Step 2: Working with Tuples, Sets, and Expressions

In MDX, a tuple is a combination of values that are used to identify a specific cell in a cube. A set is a collection of tuples that are used to identify a specific range of cells in a cube. An expression is a formula that is used to calculate a value based on the values in a tuple or set.

To work with tuples, sets, and expressions, you need to use the following MDX functions:

  • TUPLE: creates a tuple from a list of values
  • SET: creates a set from a list of tuples
  • EVALUATE: evaluates an expression and returns the result

For example, to create a tuple from the values 100 and 200, you would use the following MDX function:

TUPLE(100, 200)

To create a set from the tuples [100, 200] and [300, 400], you would use the following MDX function:

SET([100, 200], [300, 400])

To evaluate an expression that calculates the sum of the values in a tuple, you would use the following MDX function:

EVALUATE(SUM(TUPLE(100, 200)))

Step 3: Building Complex Sets

To build complex sets, you need to use the following MDX functions:

  • INTERSECT: returns the intersection of two sets
  • UNION: returns the union of two sets
  • EXCEPT: returns the difference between two sets

For example, to return the intersection of the sets [100, 200] and [300, 400], you would use the following MDX function:

INTERSECT([100, 200], [300, 400])

To return the union of the sets [100, 200] and [300, 400], you would use the following MDX function:

UNION([100, 200], [300, 400])

To return the difference between the sets [100, 200] and [300, 400], you would use the following MDX function:

EXCEPT([100, 200], [300, 400])

Conclusion

In this step-by-step guide, we have taught you the Multidimensional Expressions (MDX) query language, one step at a time. By the end of this tutorial, you will have built the core techniques for using MDX with Analysis Services. You will be able to construct and execute MDX queries, work with tuples, sets, and expressions, and build complex sets to retrieve the exact data users need.

Additional Resources

For more information on MDX, please refer to the following resources:

  • Microsoft SQL Server 2008 MDX Step by Step: This tutorial provides a comprehensive guide to the MDX query language.
  • Microsoft SQL Server 2008 Analysis Services: This documentation provides detailed information on the Analysis Services component of SQL Server 2008.
  • Microsoft SQL Server 2008 MDX Reference: This reference guide provides detailed information on the MDX functions and syntax.

Practice Exercises

To practice what you have learned in this tutorial, please complete the following exercises:

  • Construct and execute an MDX query to retrieve data from a cube.
  • Work with tuples, sets, and expressions to analyze and report data.
  • Build complex sets to retrieve the exact data users need.

Frequently Asked Questions

In this Q&A article, we will answer some of the most frequently asked questions about Microsoft SQL Server 2008 MDX.

Q: What is MDX?

A: MDX is a query language used to extract data from a multidimensional database. It is a powerful tool for analyzing and reporting data in a business intelligence environment.

Q: What is the difference between MDX and DAX?

A: MDX and DAX are both query languages used in business intelligence environments. However, MDX is used to extract data from a multidimensional database, while DAX is used to create calculated columns and measures in a tabular database.

Q: What are the basic syntax of an MDX query?

A: The basic syntax of an MDX query is as follows:

SELECT <axis> ON COLUMNS FROM <cube>

Where:

  • <axis> is the axis of the cube that you want to retrieve data from
  • <cube> is the name of the cube that you want to retrieve data from

Q: What is a tuple in MDX?

A: A tuple is a combination of values that are used to identify a specific cell in a cube.

Q: What is a set in MDX?

A: A set is a collection of tuples that are used to identify a specific range of cells in a cube.

Q: What is an expression in MDX?

A: An expression is a formula that is used to calculate a value based on the values in a tuple or set.

Q: How do I construct and execute an MDX query?

A: To construct and execute an MDX query, you need to use the following steps:

  1. Identify the axis and cube that you want to retrieve data from.
  2. Use the SELECT statement to specify the axis and cube.
  3. Use the ON COLUMNS clause to specify the axis that you want to retrieve data from.
  4. Use the FROM clause to specify the cube that you want to retrieve data from.
  5. Execute the query using the Analysis Services client.

Q: How do I work with tuples, sets, and expressions in MDX?

A: To work with tuples, sets, and expressions in MDX, you need to use the following functions:

  • TUPLE: creates a tuple from a list of values
  • SET: creates a set from a list of tuples
  • EVALUATE: evaluates an expression and returns the result

Q: How do I build complex sets in MDX?

A: To build complex sets in MDX, you need to use the following functions:

  • INTERSECT: returns the intersection of two sets
  • UNION: returns the union of two sets
  • EXCEPT: returns the difference between two sets

Q: What are some common MDX functions?

A: Some common MDX functions include:

  • SUM: returns the sum of a set of values
  • AVG: returns the average of a set of values
  • MAX: returns the maximum value in a set of values
  • MIN: returns the minimum value in a set of values

Q: How do I troubleshoot MDX queries?

A: To troubleshoot MDX queries, you can use the following steps:

  1. Check the syntax of the query for errors.
  2. Use the Analysis Services client to execute the query and view the results.
  3. Use the MDX debugger to step through the query and identify any errors.
  4. Consult the MDX documentation and online resources for help.

Conclusion

In this Q&A article, we have answered some of the most frequently asked questions about Microsoft SQL Server 2008 MDX. We hope that this article has provided you with a better understanding of the MDX query language and how to use it to extract data from a multidimensional database.