This article describes the differences between report-based tools and model-based tools. Because Power BI is a model-based tool and not a report-based tool, it is useful to have a quick reference guide explaining these differences.  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

This article describes how to optimize DAX expressions with mutually exclusive calculations that might cause slow query performance.  Read more

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

In SQL there are different types of JOIN, available for different purposes. This article shows the equivalent syntaxes supported in DAX and it was updated in May 2018.  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

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