Power Query and Data Transformation Flashcards
6 cards from real Microsoft Power BI practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Power Query and Data Transformation flashcards as text
What does the 'Group By' transformation in Power Query do?
Answer: Aggregates rows based on one or more key columns and applies operations like Sum, Count, or Average
Group By aggregates data by grouping rows with the same key column values and applying aggregation operations such as Sum, Count, Min, Max, or Average.
What is the 'List.Generate' function used for in Power Query M?
Answer: Creates a list by repeatedly applying a function, useful for iterative or recursive operations
List.Generate creates a list by iteratively applying a next-value function as long as a condition is true, enabling loop-like behavior in M.
What is a 'Custom Function' in Power Query and how do you apply it?
Answer: A reusable M function you define once and invoke against each row or value in a table
A Custom Function in Power Query is a user-defined M function that can be invoked across rows of a table using 'Invoke Custom Function', enabling reusable transformation logic.
What does the 'Conditional Column' feature in Power Query allow you to do?
Answer: Adds a new column whose values are determined by if-then-else logic on other column values
Conditional Column adds a new column with values defined by a series of if-else rules applied to existing column values, without writing M code manually.
In Power Query, what does 'Promote Headers' do?
Answer: Uses the first row of data as the column header names
Promote Headers takes the values in the first row of the table and sets them as the column header names, replacing generic Column1, Column2 names.
What is the 'Expand' button (expand table column) used for after a Merge Queries step in Power Query?
Answer: Expands the nested table column from the merged query to reveal individual columns from the joined table
After a merge, the joined table appears as a nested Table object in a new column; clicking Expand lets you select which columns from the joined table to bring into the main query.