Category: Power BI

Reza Rad has released part 1 of a series on creating date dimensions in Power BI:

When it comes to create the date (or calendar) dimension in Power BI, there is always a question: Should I create the dimension with Power Query or DAX? This is a very good question to ask. It means that you know that there are multiple ways of creating it. What is the difference? the answer is that for many scenarios these are similar. So, it might not be different to use Power Query or DAX for it. However, there is a big difference.

Power Query can fetch data from live web APIs. This functionality gives you the power to fetch public holidays live from an API. You cannot do this with DAX! Apart from this big difference, majority of other requirements can be done with both, you can write calculations in both M or DAX to get calendar columns as well as fiscal columns. In many scenarios public holidays plays an important role in analyzing data. You would like to know how the sales was in holidays compared to other holidays and etc.

There are a few more parts forthcoming, so stay tuned.

Reza Rad shows how to build merge joins between date ranges in Power Query:

Customer’s table has the history details of changes through the time. For example, the customer ID 2, has a track of change. John was living in Sydney for a period of time, then moved to Melbourne after that.

The problem we are trying to solve is to join these two tables based on their customer ID, and find out the City related to that for that specific period of time. We have to check the Date field from Sales Table to fit into FromDate and ToDate of the Customer table.

This is a common type 2 SCD scenario.  I’d be concerned that this solution would not work with large data sets which may already be pushing the size limits of the Vertipaq engine.

Matt Allington covers some of the basics of DAX:

Do I need to learn the DAX language?

You certainly do not need to know how to write DAX to get started with Power BI.  Power BI is the newest business intelligence tool that leverages the DAX language (via Power Pivot) and it is definitely possible to get started and build some reports without learning any DAX at all.   If you are a “consumer of reports” that other people produce for you then you certainly don’t need to learn any DAX.  However if you are someone that wants to do your own adhoc (or structured) analysis of data using Power BI, Power Pivot for Excel, then you will definitely want to learn to write some DAX in order to get value from what these new tools have to offer.

It’s a good intro if you aren’t familiar with DAX.

Dusty Ryan shows off What-If Analysis in Power BI:

Next, I’m going to create a calculated measure that multiples Revenue Last Year by Revenue Target % Value. Here’s the formula for the calculated measure:

Revenue Target = [Revenue Last Year] * [Revenue Target % Value]

Now I’m going to add this new measure, Revenue Target, to my line chart. And now when I use my slicer slider bar, I can dynamically change my Revenue Target line on the chart!

This is pretty cool.  Definitely check out Dusty’s example; it’s something that might make many an executive happy.

Meagan Longoria shifts our perspective by 90 degrees:

Back in January 2016, I wrote a blog post explaining a DAX workaround that allows you to put measures on rows in a matrix in a Power BI report. I’m happy to say that you no longer need my workaround because you can now natively put measures on rows in a matrix in both Power BI Desktop and PowerBI.com.

This is accomplished via a new formatting option for the matrix.

Click through to see how to pull this off.