Category: DAX

Alberto Ferrari and Marco Russo add some context:

RELATED is one of the most commonly used DAX functions. You use RELATED when you are scanning a table, and within that row context you want to access rows in related tables. RELATEDTABLE is the companion of RELATED, and it is used to traverse relationships in the opposite direction. When learning DAX, it is easy to get confused and use RELATED when it is not necessary, or to forget about RELATEDTABLE. In this article, we describe the most common uses of the two functions, along with common misperceptions.

Click through to learn more about these two functions.

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Jeffrey Wang continues a series on EVALUATEANDLOG():

Last week, we learned how to interpret the output of the EvaluateAndLog function of scalar expressions. Albeit interesting, the new function would be much less useful if it could only return scalar values. After all, Power BI users can always define a scalar expression as a measure and then study its values in various contexts. The real power of EvaluateAndLog is that it can also wrap around any table expressions, the output of which was much harder to visualize until now.

This function exposes a lot of information, as you can see in the post.

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Marco Russo has an announcement:

DAX Studio 3 was released today.

This new, major version offers a new user interface and user experience, providing a modern look and feel without losing any of the features available in previous versions. On the contrary, in DAX Studio 3, many features that were harder to reach in the past are now more visible and easier to use.

The cost of implementing a complete overhaul for a product’s user interface is typically high, but at the same time, this overhaul does not provide new features compared to previous versions. So why bother about the user interface while the product is free and open-source?

Read on to see what those changes look like.

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Chris Webb is excited:

I think this is the most exciting thing to happen in DAX since the introduction of variables. Why? Well we all know that writing DAX can be hard, and part of why it’s hard is that it’s hard to debug.

Read on to see how EvaluateAndLog() makes life easier, as well as a couple links to Jeffrey Wang’s blog for further detail.

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Barney Lawrence votes None of the Above:

Field Parameters are one of my favourite recent additions to Power BI. The ability to turn a single chart into potentially dozens changes the way we think about putting variations of visuals on the page. It was a real wow moment for a client recently when I showed how field parameters for 5 fields and 5 measures could produce a single report page that replaced 25 of their existing reports.

While they theoretically don’t allow you to do much that you couldn’t previously with a disconnected slicer and a lot of DAX they build it faster and without the need to get heavily in to coding DAX. Anything that lowers the difficulty bar for users trying to make the most out of Power BI is a good thing in my book.

There are a couple of issues Barney has with them as they stand now but there are workarounds.

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Marco Russo explains a difference:

We recently updated SUMMARIZECOLUMNS on DAX Guide by adding an example that clarifies the difference between a filter applied to SUMMARIZECOLUMNS and a filter applied to CALCULATETABLE.

Read on for an example of how summarizecolumns() normally works but how things might change a little bit when you introduce calculatetable() to the mix.

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Marco Russo and Alberto Ferrari show us how to use variables in DAX:

Variables were introduced in DAX in 2015 and so far, they have proven to be the best enhancement of the DAX language ever. When presented with the concept of variables, most newbies focus on performance improvement, thinking that you introduce variables in your code mainly to obtain better performance. Although variables can improve performance, performance is a minor advantage. There are several more important considerations that should encourage any DAX developer to make extensive use of variables. In this article we share a few considerations, along with best practices about variables and DAX.

Read on to see what makes variables so powerful.

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Soheil Bakhshi explains the concept of report-level measures:

Report level measures are the measures created by the report writers within a Thin Report. Hence, the report level measures are available within the hosting Thin Report only which means the report level measures are not written back to the underlying dataset and hence they are not available to any other reports.

Read on to see how you can create one. I don’t think I’d ever heard them called that before but the name makes sense.

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