Power BI Data Modeling & DAX Questions
Understand Power BI's data modeling concepts: relationships (one-to-many, many-to-many), cardinality, filter propagation, and bidirectional relationships. Write DAX formulas for measures and calculated columns, including basic (SUM, COUNT, AVERAGE) and advanced functions (CALCULATE, FILTER, ALL, VALUES). Understand variables and performance implications of DAX formulas.
MediumTechnical
1 practiced
Design a solution to compute "active customers" at a selected snapshot date. You have CustomerEvents(CustomerID, EventDate, EventType with values signup and churn). Describe the data model and write a DAX measure that returns the count of customers who are active as of a slicer-selected date, taking into account multiple signups and churn events.
MediumTechnical
0 practiced
There is a many-to-many scenario between Products and Promotions through Sales. A promotion can apply to multiple products and a product can be under multiple overlapping promotions. Explain three modeling options to compute sales attributable to active promotions without double-counting, and provide a DAX outline for one approach.
MediumTechnical
0 practiced
Create a DAX measure to compute a running total of Sales Amount by month partitioned by ProductCategory that respects filters on ProductCategory but ignores any filters applied to SalesRep. Model: Sales(Date, ProductID, SalesRepID, Amount), Product(ProductID, ProductCategory).
MediumTechnical
1 practiced
You have a high-cardinality product name column used only for a slicer. Keeping this text in the fact table increases model size. Propose alternatives to support user selection and implement a DAX-based Top N filter where users choose a product name from a separate dimension without duplicating the text in the fact table.
EasyTechnical
0 practiced
What is cardinality in a Power BI model and how does high cardinality affect model size and query performance? List practical techniques to reduce cardinality in a large dataset before importing into Power BI (examples: surrogate keys, bucketing, removing columns).
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