Hi, I'm Tom Blessing. I'm an expert at helping small to mid-sized companies adopt Power BI. I'm also a recovering investment banker, with deep experience applying technology to otherwise manual data problems. I have dual degrees in Finance and Technology Management from Indiana University.

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One common requirement in data modeling is adding a new column with the same value for all rows in a table.

In this blog post, I'll explore how to add a column with the same value in Power BI, which can be useful for creating calculated flags, constants, or reference columns.

Adding a Column with the Same Value

To add a new column with the same value in Power BI, you can use the "Add Column" feature along with Power Query Editor, which is a powerful tool for data transformations. 

1. Load Your Data: Open your Power BI Desktop file and load your data source by going to the "Home" tab and selecting "Get Data." Choose your data source type and connect to it. If you get stuck on this step and feel like you need a more comprehensive course to help you get started with Power BI, Datacamp has a great deal on Power BI Courses. I earn a small commission if you click and purchase. 

2. Open Power Query Editor: After loading your data into Power BI, click on "Transform Data" on the Home tab. This will open the Power Query Editor, where you can perform data transformations. 

3. Select the Table: In the Power Query Editor, select the table to which you want to add a new column with the same value.

4. Add a Custom Column: With the table selected, go to the "Add Column" tab in the Power Query Editor. Click on the "Custom Column" option. 

5. Define the Expression: In the "Custom Column" dialog box that appears, you can define the expression for your new column. To add a column with the same value in all rows (in other words, a constant), just type "=4", substituting the number 4 with whatever value you want. If you want the constant to be text, simply surround your text with quotes, like ="bananas". 

6. Specify the Data Type: You can also specify the data type for your new column. Make sure it matches the type of data you are adding. For a constant value, you may choose "Text," "Whole number," or another appropriate data type. 

7. Apply Changes: After adding the custom column, click the "Close & Apply" button in the Power Query Editor to apply the changes to your data model in Power BI.

8. Use the New Column: You can now use the newly created column with the same value in your Power BI reports, visualizations, or calculations as needed.

Benefits of Adding a Column with the Same Value

1. Data Enrichment: It allows you to enrich your data model with additional context or reference information that is consistent across all rows.

2. Flagging: You can use this technique to create flags or indicators for specific conditions or categories, simplifying data analysis and visualization.

3. Constants: It's useful for adding constants, such as default values or labels, to your data for reporting and analysis.

4. Data Validation: You can use constant columns for data validation or filtering purposes.

Conclusion

Adding a column with the same value in Power BI is a straightforward process using the Power Query Editor.

Whether you need to create flags, constants, or reference columns, this technique enhances your data modeling capabilities, making it easier to analyze and visualize your data effectively.

By following the steps outlined in this guide, you can enrich your Power BI data model to better meet your reporting and analysis requirements.