Using Group By in Power Query while Retaining All Columns -  A How-To Guide

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When using Power Query in Power BI to clean and transform your data, you may want to group your data by a specific column while keeping all the other columns in the resulting table. In this how-to guide, we will explain how to use the Group By function in Power Query while retaining all columns in the dataset.

1. Load your data into Power BI:

Open Power BI Desktop and import your data by clicking on the "Home" tab, then select "Get Data" and choose the appropriate data source.

2. Open Power Query Editor:

Once your data is loaded, click on the "Transform Data" button in the Home tab to open the Power Query Editor.

3. Duplicate the column you want to group by:

To retain all columns in the grouped data, start by duplicating the column you want to group by:

1. Right-click on the column header.
2. Select "Duplicate Column" from the context menu.

4. Group by the duplicated column:

Now, group your data based on the duplicated column:

1. Click on the duplicated column header to select it.
2. In the "Home" tab of the Power Query Editor, click on the "Group By" button.
3. In the Group By the window, select the aggregation function you want to apply to the data, such as Sum, Count, or Average.
4. Choose the column you want to perform the aggregation on from the "New Column Name" dropdown menu.
5. Click "OK" to apply the Group By operation.

5. Merge the original and grouped tables:

To retain all columns in the final result, merge the original table with the grouped table:

1. Go to the "Home" tab and click on the "Merge Queries" button.
2. In the Merge window, select the original table as the first table, and the grouped table as the second table.
3. Click on the original grouping column in the first table and the duplicated column in the second table to establish a matching relationship.
4. Choose the "Left Outer" join type to keep all rows from the first table and matching rows from the second table.
5. Click "OK" to merge the tables.

6. Expand the merged table:

After merging the tables, expand the new merged column to include the aggregated data:

1. Click on the expand button (two arrows) in the merged column header.
2. In the "Expand" window, uncheck "Use original column name as prefix" and select the columns you want to include in the final table.
3. Click "OK" to expand the column.

7. Remove the duplicated column:

Finally, remove the duplicated column used for grouping:

1. Right-click on the duplicated column header.
2. Select "Remove" from the context menu.

8. Apply and close Power Query Editor:

After completing these steps, click "Close & Apply" in the Home tab of the Power Query Editor to apply the transformations and return to the main Power BI window.

Conclusion:

By following these steps, you can use the Group By function in Power Query while retaining all columns in your dataset. This method allows you to aggregate your data based on a specific column and keep all the other columns in the resulting table, providing a more comprehensive view of your data for further analysis and visualization.

We hope you found this step-by-step guide on Power BI’s incremental refresh feature insightful and valuable. 

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