Power BI 778 Power Query and Data Transformation

Question 1

What is Power Query used for in Power BI?

Accepted Answer

Connecting to data sources and transforming data before loading

Answer

Power Query is the ETL (Extract, Transform, Load) engine in Power BI used to connect, clean, and shape data before analysis.

Question 2

What language do Power Query transformations use behind the scenes?

Accepted Answer

M (Power Query Formula Language)

Answer

Power Query uses M language, a functional language that defines every transformation step applied to your data.

Question 3

Which Power Query step removes rows where a specified column's value is null?

Accepted Answer

Filter Rows

Answer

Filter Rows allows you to filter out rows based on conditions, including removing rows where a column value is null.

Question 4

What does 'Append Queries' do in Power Query?

Accepted Answer

Stacks rows from multiple tables vertically into one table

Answer

Append Queries combines tables by stacking their rows on top of each other, similar to UNION ALL in SQL.

Question 5

What does 'Merge Queries' do in Power Query?

Accepted Answer

Joins two tables horizontally on a common key column

Answer

Merge Queries performs a join between two tables based on matching key columns, similar to a SQL JOIN.

Power BI 778 Practice Test