Categorised data in PowerBi

Question

I'd like some advice on how to categorize/group data in PowerBi.

For example, I set up a conditional column in Power Query to achieve the results seen in the "Group" column by saying if ID is 8304, then Group B, and if ID is 8660, then Group F — but the database is large, and I'm already experiencing performance issues when trying to set up a report based on individual Groups; the data takes a long time to load.

Is there a better or more efficient way to group data?

ID	Group
8015	A
8020	A
8229	A
8304	B
8389	B
8391	C
8414	D
8421	A
8469	A
8572	A
8619	F
8660	F
8663	J
9102	A
9104	K
9120	A

Answer 1

If you're experiencing performance issues when setting up a report based on individual groups in Power BI, there are a few alternative approaches you can try to improve efficiency:

1. Grouping in Power Query: Instead of using conditional columns in Power Query, you can use the Group By transformation to create a separate table with grouped data. This way, Power BI will load the pre-grouped data directly, which can improve performance. You can then establish relationships between the original table and the grouped table for reporting purposes.

2. Creating a calculated column: Instead of using conditional columns, you can create a calculated column in the Power BI data model to assign groups based on specific conditions. This way, the grouping is done within the data model, and the report will load faster since the grouping is already performed during data refresh.

3. Using DAX measures: If the performance issue persists even after trying the above methods, you can consider using DAX measures to dynamically calculate groupings during visualization rather than pre-calculating them. This can help improve performance by reducing the data size and calculations done during data refresh.

4. Utilizing query folding: Ensure that query folding is happening in Power Query to push the grouping operations to the underlying data source. This way, the database performs the grouping, and only the grouped results are loaded into Power BI. Check that your data source supports query folding and optimize your Power Query steps accordingly.

It's also worth considering optimizing the overall performance of your Power BI report by evaluating other factors such as data volume, data model complexity, and visualizations. Additionally, ensuring your data sources are properly indexed and optimized can significantly impact performance.

By employing these techniques, you should be able to enhance the performance of your Power BI report when grouping data.

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