This article describes how blank values considered in a DAX conditional expression can affect its query plan and how to apply possible optimizations to improve performance in these cases.  Read more

I often get questions about use cases for Azure Analysis Services. So I wanted to do a quick recap of the points I commonly discuss in these conversations, and have them readily available for the next conversation… As a bonus,…  Read more

This article provides information to help choose between DAX and Power Query when a table needs to compute additional columns.  Read more

In 2015 I released the first version of VertiPaq Analyzer, a tool to quickly analyze the structure and data distribution of a Tabular model that can be used with Analysis Services and Power BI.  Read more

The second edition of The Definitive Guide to DAX is now available worldwide! This blog post explains why we felt the need to rewrite the book and describes what happens behind the scenes when producing a book.  Read more

Microsoft announced at SqlBits a very important feature for DAX: Calculation Groups. These are my first impression about the new feature and the impact it will have on Analysis Services and Power BI.  Read more

This article describes how DAX automatically converts data types in arithmetic operations. These small details can cause and explain differences in results when using the same operations in other languages.  Read more

This article describes how to use the detail rows expression of a measure to obtain the equivalent of creating table functions in DAX. This allows the reusing of a table expression in multiple CALCULATE filters.  Read more

When you create a Tabular model for Analysis Services, the Culture and Collation properties are set automatically and cannot be changed by the SSDT user interface in Visual Studio. The biggest issue is the workspace database, because these properties cannot…  Read more

This article provides a complete explanation of the behavior of the ALLxxx functions in DAX. When used as filters in CALCULATE, ALLxxx functions might display unexpected behaviors.  Read more