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

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

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

Understanding the difference between row context and filter context is important in using DAX correctly. This article introduces these two concepts.  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 relationships in a data model queried by DAX are a fundamental part of the engine and simplify the query itself. This article examines the cost of relationships in a data model, providing hints to optimize them.  Read more

ALLSELECTED looks like a special function that is able to understand what the user selected in the pivot table, retrieving the original filter context under which the pivot table is running. However, how it is possible that a DAX function…  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

DAX is a functional language that does not allow you to create functions. However, if you need to pass a parameter to an algorithm, you can use a measure passing a value through a filter argument in CALCULATE, as described…  Read more