Professional Microsoft SQL Server 2012 Analysis Services with MDX and DAX

Chapter 18

Introduction to DAX

What's in this chapter?

• Introducing DAX language
• Introducing row context and filter context
• Categorizing DAX functions
• Discussing DAX usage
• Comparing DAX with MDX

DAX, an acronym for Data Analysis Expressions, is a language used to define and manipulate calculations as well as query data from tabular Business Intelligence Semantic Models (BISM). DAX was first introduced as part of PowerPivot for Excel, an Excel add-in for information workers to import, integrate, and analyze multiple tables with the help of calculations they were defining using DAX. In SQL Server Analysis Services 2012, DAX is supported against tabular BISM with additional enhancements including using DAX as a query language for clients to query data against tabular BISM. DAX provides a set of functions for business intelligence (BI) calculations, which are similar to Excel formulas, and there is overlap between the list of DAX functions and Excel functions. There are differences, and DAX contains new functions that don't exist within Excel. These DAX functions are designed to offer capabilities that focus on data analysis, particularly for related tables of data, and for dynamic analysis. The ability to define calculations that can be evaluated dynamically in many different contexts is a powerful tool, and prior to PowerPivot and DAX, these sorts of calculations often involved more complex multidimensional concepts and languages.

Excel users can learn how to perform data analysis ...