When you encounter a situation where there are duplicate rows in your Power BI matrix or table visual or the table visual displays incorrect totals, this is usually connected either to the relationships of the tables, to the data model, or to the way you defined measures and used aggregations in DAX. Below are a few possible causes and approaches that you may follow to try and fix these needs.
1. Verify Table Relationship
Usually, duplicate rows will be more visible when there is confusion between tables regarding relationships. Say, for instance, you have a one-to-many or many-to-many relationship wrongly configured; such a scenario will lead to needless duplications or geographies aggregating inaccurately. Switch to the ‘Model’ view in Power BI and check all relationships. It is advisable to make any key columns on the single side of a relationship unique as well as for many–to–many relationships; it should be for some explicit reason such a relationship exists. If there are complex connections among multiple tables, adding a bridge table may also help.
2. Examine your DAX Measures
Another frequent reason for incorrect totals is the formulation of the DAX measures. For example, suppose simple aggregation functions (for instance, SUM or COUNT) are applied to the DAX measures, and one of the levels of filtering contains duplicate values. In that case, this may lead to an erroneous increase in the values of totals. However, it is recommended that DAX functions such as SUMX or CALCULATE be applied with filters in order to control aggregation totals correctly. It is also possible to use such functions as DISTINCT or some other function to change the context in order to avoid duplicates, where required.
3. Set Up Data Hierarchies Properly
If you’re working with hierarchical data, such as regions that break down into countries and cities, ensure that you’ve set up the hierarchy correctly in Power BI. An improperly configured hierarchy can sometimes result in duplicated rows when data is summarized at higher levels. You can create and manage hierarchies in the “Fields” pane, which can help organize the data visually without introducing duplicates.
Final Tips
After making changes, refresh your visuals to see if the problem persists. Also, try temporarily removing or altering filters to see if they impact the duplicates or totals. If needed, you can use Power BI’s “Drillthrough” feature or export the data to Excel to manually inspect and identify where the duplication may be occurring in the underlying data. These steps should help you pinpoint the issue and achieve accurate, consistent data displays.
