power BI or tableaue (choose one)

Power BI – Detailed Tutorial #

Introduction to Power BI #

Power BI is a tool used to:

• Import data
• Clean & transform data
• Create dashboards
• Build reports

Workflow:
Data Source → Power Query → Data Model → DAX → Visualization

Connecting Data Sources #

What is Data Connection? #

It means importing data into Power BI from different sources.

Common Data Sources #

• Excel files
• CSV files
• SQL databases
• Web APIs
• Cloud (Google Analytics, Azure, etc.)

Steps to Connect Data #

1. Open Power BI Desktop
2. Click Home → Get Data
3. Choose source (e.g., Excel)
4. Select file
5. Click Load or Transform Data

Example #

Import Excel Sales Data:

• Select Excel file
• Choose sheet
• Load into Power BI

Load vs Transform #

Data Transformation (Power Query) #

What is Power Query? #

Power Query is used to clean and prepare data before analysis

It’s similar to Excel data cleaning but more powerful

Opening Power Query #

Click Transform Data

Common Transformations #

Remove Columns #

• Remove unnecessary data

Right-click column → Remove

Rename Columns #

• Make names clear

Double-click column name

Change Data Type #

Remove Duplicates #

Home → Remove Rows → Remove Duplicates

Filter Data #

Use filter dropdown

Split Columns #

Transform → Split Column

Example:
“Alex John” → First & Last name

Add New Columns #

Add Column → Custom Column

Example Transformation #

Raw Data:

" Alex , 100 , 2025 "

Steps:

• Trim spaces
• Split columns
• Convert types

Clean dataset ready

Apply Changes #

Click Close & Apply

DAX (Data Analysis Expressions) #

What is DAX? #

DAX is a formula language used in Power BI to:

• Create calculations
• Build measures
• Analyze data

Types of DAX #

Basic DAX Functions #

SUM #

Total Sales = SUM(Sales[Amount])

AVERAGE #

Avg Sales = AVERAGE(Sales[Amount])

COUNT #

Total Orders = COUNT(Sales[OrderID])

IF Function in DAX #

Status = IF(Sales[Amount] > 100, "High", "Low")

CALCULATE (Important) #

Definition #

Changes filter context

Example #

High Sales = CALCULATE(
    SUM(Sales[Amount]),
    Sales[Amount] > 100
)

DAX with Filters #

Sales East = CALCULATE(
    SUM(Sales[Amount]),
    Sales[Region] = "East"
)

Example Dashboard Measures #

• Total Sales
• Sales by Region
• Monthly Sales

Workflow Example #

1. Connect Excel data
2. Clean in Power Query
3. Load data
4. Create DAX measures
5. Build visuals

Summary Table #