This article describes a very common optimization pattern that relies on variables to optimize conditional expressions in DAX.  Read more

This article describes the behavior of the COMBINEVALUES function in DAX, and how it can optimize the performance of DirectQuery with multi-column relationships.  Read more

A recurring issue for Power BI users writing DAX code is that column filter removal might have an unexpected behavior when the Sort by Column is active on the column. I covered this topic in an article related to RANKX,…  Read more

This article describes how to implement in DAX a logical OR condition between the selection of two slicers of a Power BI report or of a PivotTable in Excel. By default, when relying on more than one slicer they are…  Read more

Expanded tables are the core of DAX; understanding how they work is of paramount importance. This article provides a theoretical foundation of what expanded tables are, along with fundamental concepts useful when reading DAX code.  Read more

This article describes how to use DAX Studio to capture DAX queries generated by Power BI. Analyzing DAX queries can be helpful to better understand performance issues, and to improve the writing of DAX queries.  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

This article describes a reference Date table in DAX using a Power BI template. The same technique can be used in Analysis Services models. Download the latest version of the template in the Dax Date Template page.  Read more

If you import more than one table into Power BI or Power Pivot, you have a data model. When you have more than one table, you usually have relationships between tables. When you analyze data, you often have many choices…  Read more

ALLSELECTED is a powerful function that can hide several traps. This article is an in-depth analysis of the behavior of ALLSELECTED, explaining shadow filter contexts, what they are and how they are used by ALLSELECTED.  Read more