The context transition in DAX is the transformation of row contexts into an equivalent filter context performed by CALCULATE and CALCULATETABLE. Managing this behavior is the next step in learning DAX once you understand row context and filter context. This…  Read more

The blank value in DAX is a special value requiring particular attention in comparisons. It is not like the special null value in SQL, and it could appear in any conversion from a table expression. This article explores in details…  Read more

One of the first concepts to learn in DAX is the difference between calculated columns and measures. This article shortly recaps the differences and describes when to use each one.  Read more

The SQL functions IN and EXISTS are useful to implement tests over a set of values. This article describes the corresponding syntax in DAX language.  Read more

Analyzing table and column size is an important step in optimizing a data model for Power Pivot, Power BI, or Analysis Services Tabular. This article describes VertiPaq Analyzer, an Excel workbook to analyze detailed information extracted from Dynamic Management Views.  Read more

When you apply a multiple selection to a slicer or to a filter, you obtain a logical OR condition between selected items. This article shows how to implement a logical AND condition in a measure instead of the standard OR…  Read more

In the 2015 September update, Power BI introduced calculated tables, which are computed using DAX expressions instead of being loaded from a data source. This article shows the usage of calculated tables to solve the pattern of transition matrix for…  Read more

This article describes how to implement a custom year-over-year calculation in DAX based on arbitrary associations between different periods. As an example, we describe the comparison of the 53rd week in a ISO Calendar.  Read more

Hardware and virtualization settings have a big impact on Analysis Services Tabular performance. This article describes best practices for the most important settings to check.  Read more

Understanding the difference between row context and filter context is important in using DAX correctly. This article introduces these two concepts.  Read more