When I embarked on my Power BI journey I was almost immediately slapped with an onslaught of foreign and perplexing terms that all seemed to do similar, but somehow different, things.
T_here is a language called M but there is also a language called DAX? What is the difference between a calculated column and a measure? When should I be using Power Query?_
I got stuck really early in my journey trying (and failing) to understand some key concepts that made Power BI seem much more difficult and confusing than it is. I almost abandoned my BI ambitions to crawl back to my familiar pal, Excel. Better the devil you know, right? WRONG!
I am so, so, SO happy that I kept banging my head against the wall to get over those initial hurdles. Today, I use Power BI almost daily, and I use it cheerfully, _gleefully _even, and I rarely use Excel. But getting here was hard, really hard. And it was harder than it should have been because, for a long time, I did not have a clear, conceptual understanding of some key Power BI concepts.
I am going to try to keep things as simple as possible to give you just a hint, a tinge, a _taste _to get you started.
More experienced Power BI users might cringe at the way I am (over) simplifying and reducing these concepts, but you know what? At this point, all of the nuance and minutia really doesn’t matter. You need a place to start. Trust me, the complexity will come.
So, my intrepid warrior, my Padawan, my Power BI master-to-be, here is a very basic overview of:
- Power Query and M
- DAX
- Calculated Column and Measures
- Power Query vs. DAX
Power Query and M
What the heck is it? This is where it all begins. Power Query is where you pull your data into Power BI. M is the coding language used by Powery Query. You can use Power Query by pointing and clicking and the code in M will essentially be created for you. You can also write your own code in M directly.
When do I use it? To clean and format your data. You can do things like remove and add columns, filter out data, change column formatting, etc.
Do I have to use M?: Short answer, no. You can do most things in Power Query by pointing and clicking without needing to use M at all. However, knowing M can be really helpful in making your process more flexible and easier to replicate in the future. For example, when using M you can copy and paste bits of code you want to reuse and you can annotate your steps.
Tip for learning: Do what you need to in Power Query by pointing and clicking and then open the Advanced Editor. The M code will be there for the manipulations you have just completed. This way, you can start to get familiar with the language and by making small tweaks before you try writing your own M code from scratch.
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