Hello!
The other day on the PUG Barcelona whatsapp group there was a question regarding the possibility of reversing the selection on a slicer, with a single click. Apparently this is something you can do on Qlik and the fellow member was trying to migrate that to Power BI as the users are used to be able to do it. I thought that you can get somewhat close to that with a calculation group, so why not write a nice short article on it. Let’s do it!
Hello!
Today (well yesterday by the time I have finished writing this) saw a great use case of calculation groups and I wished I had come up with the idea myself because it’s awesome and something that I’ve come across sometimes. In a table there’s a breakdown by month, and at the total they want to see sum, but also want to add another column with say the average, but could be also the value last year or growth. Yes, I’m talking about the latest video from Chandeep Chabbra. The video is beautifully set up so it’s definitively worth a watch.
Even though there’s a few things I would change from the DAX of the format string expressions, that alone would not justify a blog post about the same use case. But yet I wanted to play with the calc group, so what I plan to do instead is to show you the process to «industrialize» this calculation group, i.e. how to create a script that will replicate similar logic whenever you want to use it. Yes, I mean a c# script. That’s something I’ve been doing lately in some sessions, but it’s not yet in the blog so why not use this occasion for it.
Hello,
today I’m not writing any type of tutorial. I just want to share a weird behavior I have found in calculation groups, hoping that those that really know about the inner workings can help us comprehend why they behave like that. Calculation groups can be seen as groups of pairs of DAX expressions that replace measures and their format strings when they are in a filter context where they participate. There’s quite a few articles that explain calculation group precedence, but when a calculation item is applied, how are the values of SELECTEDMEASURE and SELECTEDMEASUREFORMATSTRING evaluated? are they the values and format string *before* anything is applied? What happens if we include SELECTEDMEASURE inside the format string expression or SELECTEDMEASUREFORMATSTRING inside the value expression? If your head is about to explode, you are not alone.
In the different posts of this blog I’ve reached different conclusions in different articles, so today I want to present two examples to deepen in this topic — during this process I hope to understand it more!
Hi! actually I was writing another blog post, but today I was shown something that can be done with calc groups that I wasn’t aware of. And not only that, even though the blog post I was shown had some very clever thinking behind, I found there’s still some room for improvement to bring the technique to the next level. We are talking about sorting a matrix by a calculation item placed at the columns section. Let it be said that in many use cases you might be better of just generating the measures with a script (as I showed in this blog post) and using the measures instead. That will give you more control with the UI since each column is indeed a different measure. Yet, there’s something cool in doing things in different way, so I’ll go ahead nevertheless.
Hello there, yes, a third part of the snapshot report and I’m not even sure it’s the last one. The thing is that since the last post there has been some major improvements on the set up that I thought are worth sharing. In my previous post I ended up with a small defeat. There were some combinations of filters that when I drilled through to see all the historic records of those order IDs I would not get any rows. Also my set up included duplicating the fact table which is a big no-no in most use cases and a shameful solution from a modeler perspective. Even though this was the best I had, I decided to present the topic on two events, one was the Data Community Day Austria 2023 and the other was @PowerBIEspanol Virtual Conf 2023 (Fin Tour Power BI Days), just a few days apart. The fact that I had to present the solution to a lot of people kept me thinking and looking for solutions, so with the help of the always reliable Ricardo Rincón I finally found out a working solution just duplicating dimension tables and creating dimension tables for everything (even comments and stuff like that). That was much better but not quite scalable. In real life things are ugly and tables have many columns. So while fighting with the same use case at work, I found a sneakier and much better solution that got rid of all those superfluous dimension tables reducing the need of them to just 2. While preparing the presentations I also worked a bit on the report layer and I’ll also share some techniques I came up with that can be helpful at some point. But enough of all this talking, let’s do what? Let’s get to it.
Well, I was happy with the result, but I was even more happy with the reaction on twitter. The dynamic header effect felt like magical to many people, and well, I have many more followers now, thank you all.
In case you haven’t seen it, here’s the video
So how did I do it? Short answer: Field parameters. A little longer answer: Measures and a calculation group create more measures that are put in field parameter with some customization.
Even longer answer? Let’s do it.
Hello again. You didn’t think there would be a second part, right? well, me neither. But as things turn out, I had to work on another report dealing with snapshots, and this time they wanted something fancier. It took me a while to figure it out, but I like the result so I thought it would be nice to share. In the first part, we just showed what went up and what went down, being able to go back and check any snapshot. However, in many use cases that does not tell the whole story. To explain why something went up or down, you need to show what went in, what went out (sometimes important to tell which way it went) and maybe even if the value changed between snapshots. If we just compare 2 consecutive snapshots is not that hard, but things get trickier we take longer time spans and we want to account for everything that happened in between.
Lately I’ve been building a report, which had not happened for a while, and I enjoyed the process. The final result too is simple yet effective, so I thought I would share the approach here because, yes, there is a calc group in place that does some of the magic.
This approach is valid when you want to follow the status of something, warehouse inventory, accounts pending to be conciliated, parking occupation. In all these situations, you are likely to be more interested in the latest snapshot than the previous ones, but at the same time you might be interested in the trends that lead to the present picture, and maybe even go back to a previous shapshot to have a look, without too many clicks. As you can see we’ll need to be smart about the date filter. For some elements we want the last snapshot only for others all of them, and yet we want we want the charts to interact.
Well it’s no secret that I like calc groups. But it’s also true that calc groups have an achiles heel. Calc Item names are constant, so for charts, legends stay the same no matter what. Depending on your use case you might get away with it, but sometimes you might get an end user that will not buy it — and he or she might be an important person, so it’s always good to have a Plan B. Field Parameters have brought fresh air, and indeed are great for such use cases because it’s not like you modify the DAX of the measure in the chart, you actually change the measure, so the name shown in the legend also changes, which is great. However, what happens if you want to create a chart where the user can pick from 4 KPI’s and say 8 time intel calculations?? First you’ll have to create the measures, then the field parameter, then figure out how to model that for the user to be able to select measure and calculation intependently… I mean it’s not impossible, but looks long and boring. Let’s see what we can do about it!
Hi, today I want to talk about inactive relationships. Those relationships with the dashed line that unless you invoque them with USERELATIONSHIP they do nothing. The thing is a common pattern if you read this blog — let’s say you have a retail model, and for some charts you need to use the order date and in other charts the delivery date. Other than that measures are the same, such as Sales amount, total cost, margin etc. Well, you could do a copy of each of the measures and wrap it in a CALCULATE( … USERELATIONSHIP(… ) ) or do a calculation group. Today we’ll do that, with style.
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