A recent change in the DAX language transformed the behavior of IF statement, so that it should not return BLANK but only TRUE/FALSE if the results should be logical expressions. In that case, the BLANK is transformed in a FALSE condition. For example, consider that the result of the following expression is FALSE and not BLANK: IF ( 1 = 1, ...

If you are used to virtual relationships in DAX (see Handling Different Granularities in DAX), you probably use the following pattern relatively often: [Filtered Measure] := CALCULATE (     <target_measure>,     FILTER (         ALL ( ...

Microsoft Press released a free eBook you can already download, Introducing Microsoft Power BI, which I and Alberto Ferrari wrote in the last few months. Please note it is a very introductive book, don’t expect an inside-out. As we wrote in the introduction: We wanted to write an introduction to Power BI that covers the basics of ...

I wrote an article about Time Intelligence in Power BI Desktop to explain how to fix measures using DAX functions for time intelligence when you have a data model where the relationship uses surrogate keys. THe short description is that all the time intelligence functions in DAX makes two assumptions: you have a ''full'' date table (all days ...

If you are using Power BI Desktop or Power Pivot in Excel 2016, you should learn when and how you can use GROUPBY instead of SUMMARIZE. The SUMMARIZE function is very powerful and internally very complex, so it’s easy to find scenarios where you get unexpected results or you have performance issues. The new GROUPBY function (also available in SSAS ...

In a couple of weeks, I will move to Australia for 3 weeks, visiting Melbourne and Sydney for a number of events and training. This is the list of topics in public events you can attend (with link to registration pages – remember that SQL Saturday conferences are free events, but you still have to register first!): UPDATE 2016-02-08 - added a ...

Last week we launched a new page in SQLBI website: DAX Puzzle (you can also use www.daxpuzzle.com). The idea is very simple: we describe a scenario, we ask to solve a problem in that scenario and we might provide some hint to help you finding the solution. You can download a sample file (in Power BI Desktop, which is freely available to anyone – ...

I am so happy to announce that The Definitive Guide to DAX is finally available! I and Alberto Ferrari spent one year writing this book, and several years collecting the knowledge necessary to do that. The complete title is The Definitive Guide to DAX: Business intelligence with Microsoft Excel, SQL Server Analysis Services, and Power BI. You can ...

Almost 3 years ago I wrote an article with the rules for DAX code formatting. If you quickly look at the article, you might think that it is all about readability of the code, and this is fundamentally true. But there two rules that have a particular importance for performance, too: Never use table names for measures Always use table names ...

The growing adoption of Power BI Desktop is gathering new users of the DAX language. At the same time, there are a few new features, such as bidirectional filter propagation, that introduce new concepts to existing knowledge. For this reason, in the last weeks we published two articles describing important basic concepts and clarifying the ...