What TOPN does
Return the top rows based on a sort expression. In Power BI, the key is not only the formula itself but how it behaves with slicers, relationships, visuals and totals.
Syntax or pattern
TOPN(n_value, table, orderBy_expression, [order])5 practical business examples
TOPN in a sales report
Create a table expression grouped by product.
Top 10 Products = TOPN(10, Products, [Total Sales], DESC)Useful for calculated tables and advanced measures.
Add sales to customer list
Add a measure result to each customer row.
Top 10 Products = TOPN(10, Products, [Total Sales], DESC)Good for analysis tables.
Select key columns
Create a narrow table for a calculation.
Top 10 Products = TOPN(10, Products, [Total Sales], DESC)Use this to control table shape.
Top products table
Return only the highest selling products.
Top 10 Products = TOPN(10, Products, [Total Sales], DESC)Useful in calculated tables and ranking patterns.
Compare missing products
Find products in one list but not another.
Top 10 Products = TOPN(10, Products, [Total Sales], DESC)Useful for reconciliation checks.
Common mistakes to avoid
- Using TOPN before checking whether the data model has the right relationships and filter direction.
- Writing one complex measure instead of creating simple base measures first.
- Testing only at the total level and not checking row, category and date contexts.
- Forgetting that slicers, visuals and relationships can all change the filter context.
FAQ
When should I use TOPN in DAX?
Use TOPN when the calculation pattern matches the business question and the result behaves correctly in the current filter context.
Why is my TOPN measure returning the wrong total?
Most total issues come from row context, filter context, relationships, or using a column aggregation where an iterator or CALCULATE pattern is needed.
Can I use this TOPN pattern in a calculated column?
Some patterns work in calculated columns, but most reporting calculations should be measures so they respond to slicers and report filters.