It's not that often that I see many posts about DAX. Despite the Data Analysis Expressions being used in Power BI, it seems that relatively few people call this out in their work. Chris Webb writes about it often, and this week is no exception. There's also a short piece on time series from Philip Seamark and another one on optimizing expression from Marco Russo.

DAX came out of the Analysis Services world and was the way that Microsoft expected people to analyze data in PowerPivot. That never quite became as popular as Microsoft hoped, but the expressions were folded into Excel and still heavily used in SSAS, but it's really become the way that you can assemble amazing reports in Power BI. If you're looking to get started, you might check out the Guy in a Cube, Adam Saxton, and his videos on DAX.

DAX isn't a native part of Excel, despite the fact that many of the functions are similar or even have the same name. You can use these expressions in the PowerPivot tab in Excel, which you can easily enable. Once you've done this, then the power of complex analysis using DAX is available for you.

Should you learn DAX? That depends. If you need to build reports, or your users are asking for help with more complex analysis, then this might be a skill that helps your career. Your users will appreciate the way in which they can view data with more complex time series and statistical functions available. This seems especially valuable when looking at data across time, like comparing previous periods to current ones.

As I look around, there are seemingly endless ways in which you can express your creativity with DAX to build more interesting reports. Some of these techniques are useful, some just fun (or perhaps silly), but a change of pace or a new view can help users become more engaged in your reports. They can be fun to build as well.

Just remember that ultimately you need to use DAX to solve problems and generate insights. Whether you use Power BI, SSAS, or just PowerPivot, don't build complex reports just because you can. Make sure you understand how the functions enable you to analyze data and the meanings behind their results. 

If you're looking to get started, we have a great Stairway Series on DAX that can help you, in addition to watching the Database Weekly newsletter for new resources every week.