📘 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!