Inserting New Columns

There are two primary ways to add columns in PowerBI: through Power Query (during data import) or DAX (after data load).

Method 1: Power Query (Recommended)

This is best for performance as the transformation happens before loading.

1. Click Transform Data to open Power Query Editor.
2. Go to the Add Column tab.
3. Select Custom Column.
4. Write your logic using M language (e.g., [Unit Price] * [Quantity]).

Method 2: DAX Calculated Column

Best if you need to use relationships to other tables.

1. Go to Table View.
2. Click New Column in the ribbon.
3. Type your DAX formula:

   Profit = Sales[Revenue] - Sales[Cost]
   

Prefer Power Query for static data cleanup and DAX for aggregations required at report time.