How to Copy a Column in Power BI

Copying a column in Power BI is a fundamental task you'll encounter frequently, whether you're preserving original data before making changes, creating a variation for a new calculation, or staging data for a specific visual. This article will show you three distinct methods for copying or duplicating a column in Power BI, explaining when and why you should use each one.

Why Copy a Column in Power BI?

While it might seem redundant at first, duplicating a column is a cornerstone of good data modeling and report building. It gives you the flexibility to transform and analyze data without destructively editing your original source columns. Here are a few common scenarios where you'll need to copy a column:

• Data Transformation: You might need to change a column's data type, split it into multiple columns, or replace values. Duplicating the column first allows you to perform these operations on the copy while keeping the original data intact for reference or other calculations.
• Creating Calculated Columns: Often, you need to create a new column whose value is based on an existing one. For example, you might create a "Due Date" column by adding 30 days to an "Invoice Date" column. While you can do this in one step, copying the column first can make the process clearer.
• Conditional Logic and Grouping: Duplicating a column is useful when applying conditional formatting or creating custom groups. You could copy a "Product Category" column to create a broader "Product Group" column, simplifying your visuals.
• Multiple Uses of the Same Data: A single column might serve different purposes. For example, a date column could be used once for its actual date value and again (in a duplicated, text-formatted version) to extract just the month or year for a slicer.

Method 1: Duplicating a Column in the Power Query Editor

The Power Query Editor is the most common and generally recommended place to perform data preparation tasks like duplicating a column. This method modifies the data before it's loaded into your Power BI data model, making it highly efficient. It permanently adds the new column to your table design.

There are two quick ways to do it within Power Query.

Using the "Add Column" Tab

The ribbon interface provides a straightforward path to duplicating your selected column.

1. Navigate to the Home tab in Power BI Desktop and click on Transform data. This will open the Power Query Editor.
2. In the preview window, find and select the column you want to copy by clicking on its header.
3. Go to the Add Column tab in the ribbon at the top of the window.
4. Within the "General" group, click the Duplicate Column button.

Power BI will immediately create a copy of your selected column at the far right of your table, usually naming it "[Original Column Name] - Copy."

Using the Right-Click Menu

For an even faster workflow, you can use the context menu directly on the column header.

1. With the Power Query Editor open, find the column you need to copy.
2. Right-click on the header of that column.
3. A context menu will appear. Select Duplicate Column from the list.

This achieves the exact same result as using the ribbon. Once the column is duplicated, it’s a best practice to immediately rename it to something descriptive. Simply double-click on the new column's header, type a meaningful name (e.g., "Invoice Date for Sorting"), and press Enter.

Method 2: Creating a New Column with DAX

Another powerful way to copy a column is by using Data Analysis Expressions (DAX). Unlike Power Query, DAX creates a calculated column after the data has been loaded into the model. This means the DAX column exists within the Power BI 'Analysis' layer, not in the initial query source.

This approach is best when the "copy" needs to be dynamic or calculated based on the data model context, perhaps involving data from other tables.

Here’s how you can create a simple 1-to-1 copy of a column using a DAX formula:

1. In Power BI Desktop, navigate to the Data View (the grid icon on the left side panel) or the Report View.
2. From the "Fields" pane on the right, select the table that contains the column you want to copy.
3. This will open the Table tools tab in the ribbon. Click on New column.
4. The formula bar will appear at the top. Here, you'll write a simple DAX expression.
5. Use the following syntax to create a direct copy:

New Column Name = 'TableName'[Original Column Name]

Example

Let's say you have a table named Sales with a column called Revenue. To create a copy of it called Revenue Backup, you would use this formula:

Revenue Backup = Sales[Revenue]

Press Enter, and Power BI will create a new column in your Sales table with the exact same values as the Revenue column. While this creates a copy, the true power of DAX is in creating subtly different versions. For example, you might create a new column for revenue including a 2% processing fee:

Revenue With Fee = Sales[Revenue] * 1.02

This is technically no longer a direct copy, but it's a common use case that starts with the principle of duplicating a column's logic.

Choosing the Right Method: Power Query vs. DAX

You have two great options, but which one should you choose? It depends entirely on your goal.

Use Power Query (Duplicate Column) when:

• You are doing prerequisite data cleaning and preparation.
• You need a physical, static column that won’t change based on report filters.
• You plan to use the new column for further transformation steps within Power Query (e.g., splitting, changing data type, extracting text).
• You want to maximize performance, as the transformation is done once during data refresh and compressed efficiently in the model.

Use DAX (New Column) when:

• You need a column that performs a calculation row-by-row and takes other DAX measures or data from related tables into account.
• The logic is dynamic and needs to be evaluated based on the data model's context.
• You forgot to create the column in Power Query and don't want to go back and trigger a full data refresh.

As a rule of thumb, if you believe the column truly belongs in the source data (and you might need it for a data relationship), make it in Power Query. If it's a column purely for a specific analysis or calculation in a report, DAX is the right tool.

Method 3: Copying a Column’s Contents to an External Application

Sometimes, "copying a column" means you literally want to copy its values and paste them somewhere else, like in a Microsoft Excel sheet or a text document. Power BI makes this simple from the Data View.

This method is useful for quick data validation, sharing a list of values with a colleague, or creating a one-off report outside of Power BI. Here are the steps:

1. In Power BI Desktop, go to the Data View.
2. Find the table and the column whose values you want to export.
3. Right-click on the column's header.
4. From the context menu, select Copy column.

This action copies all the values in that column to your clipboard. You can now switch to Excel or another application and paste the data. Keep in mind that this might be slow or hit memory limits for columns with millions of rows.

Final Thoughts

Knowing how to copy a column gives you incredible flexibility in how you prepare, model, and present your data in Power BI. Using Power Query to duplicate columns is best for foundational data shaping, while a DAX calculated column provides powerful, dynamic analysis capabilities right inside your reports.

Constantly duplicating columns, stitching together datasets, and wrestling with tools like Power BI is precisely why we built Graphed. If you're building marketing and sales reports, you can connect your data sources (like Google Analytics, Shopify, and Salesforce) and just describe the dashboard you want in plain English. There’s no more need to manually duplicate columns for sorting or transformations, you can just ask, "Show me traffic by source, but group an 'Organic' category for Google and Bing" and let our AI handle the rest.