Beginner’s Guide to Power BI: DAX, Measures, and Learning by Doing

📘 My Power BI Journey (So Far)

I recently started learning Power BI, and honestly? It’s been a wild but rewarding ride.

As a beginner, I wasn’t sure what to expect. I’ve used Excel before, sure—but Power BI is a different beast. I wanted to write this to share what I’ve learned so far (especially about DAX) and maybe help someone else just starting out like me.

🎨 Power BI Isn’t Just Drag & Drop

When I first opened Power BI, it felt pretty intuitive- load data, drag fields onto visuals, and boom: charts. But pretty soon, I realized I’d need to dig deeper to get the insights I wanted.

That’s when I met DAX.

🧠What Is DAX?

DAX stands for Data Analysis Expressions. It’s the formula language that lets you do calculations inside Power BI.

If you’re used to Excel, it feels a bit familiar... but it definitely plays by different rules.

🔍 Calculated Columns vs Measures

So here’s how I finally made sense of it:

📌 Calculated Columns: These are new fields added to your data table, row by row.

Example

FullName = Customers[FirstName] & " " & Customers[LastName]

Think of it like “baking” the value into your data.

📌 Measures: These are dynamic calculations that change based on filters and visuals.

Example

Total Sales = SUM(Sales[Amount])

They’re not stored in the table; they get calculated on the fly.

At first, I used calculated columns for everything—big mistake. Now, I try to stick to measures unless I really need a physical column.

📐 Some Basic DAX Formulas I’m Using

Here are a few beginner-friendly DAX functions I’ve been using a lot:

➕ SUM(): adds up values
📊 AVERAGE(): gives the average
🔢 COUNTROWS(): counts the rows in a table
🔁 CALCULATE(): changes the context of a measure (powerful, but confusing!)
⚙️ IF(): basic logic, like in Excel

🔄 Power Query vs DAX (Yes, They’re Different)

This also tripped me up: why do Power BI and Power Query both have formula languages?

Here’s how I understand it now:

🧹 Power Query is for cleaning and shaping your data before it reaches the model.

📊 DAX is for analyzing and calculating stuff after your data is loaded.

In short

Power Query = Prepare the data
DAX = Analyze the data

Both are important, but they do very different jobs.

🧩 Still Wrapping My Head Around…

How CALCULATE() works under different filters
What exactly “filter context” and “row context” mean
When to use ALL() or REMOVEFILTERS()

💬 Final Thoughts (And a Quick Thanks)

I’m still learning, and I’ll probably always be learning, but that’s kind of the fun part.

Huge thanks to the Power BI community (especially here on C# Corner!)—you’ve all helped me without even knowing it.

If you’ve got any tips, beginner mistakes to avoid, or cool DAX formulas, I’d love to hear them in the comments!