Removing duplicates in Power BI - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does 'removing duplicates' mean in Power BI?

It means deleting repeated rows in your data so each record is unique. This helps keep your reports clean and accurate.

beginner

Which Power BI tool is commonly used to remove duplicates?

Power Query Editor is used to remove duplicates by selecting columns and choosing 'Remove Duplicates'.

beginner

How do you remove duplicates from a specific column in Power Query?

Select the column, then click 'Remove Duplicates' in the Home tab. Only unique values in that column remain.

intermediate

What happens if you remove duplicates based on multiple columns?

Power BI keeps rows unique across all selected columns combined, removing rows where all those columns match another row.

intermediate

Can you remove duplicates using DAX in Power BI?

DAX does not remove duplicates from tables directly but you can create calculated tables or measures that summarize unique values.

Which Power BI feature is best for removing duplicate rows?

A Data View

B DAX Measures

C Power Query Editor

D Report View

Power Query Editor is designed for data transformation tasks like removing duplicates.

What does 'Remove Duplicates' do when applied to one column in Power Query?

A Deletes all rows with repeated values in that column

B Keeps only one row for each unique value in that column

C Deletes the column

D Sorts the column alphabetically

It keeps one row per unique value, removing extra rows with the same value.

If you select multiple columns and remove duplicates, what is the result?

A Rows with duplicate values in any one column are removed

B Only the first column is checked for duplicates

C Duplicates are highlighted but not removed

D Rows are removed only if all selected columns have duplicate values

Duplicates are removed only when all selected columns match another row.

Can you remove duplicates directly in a DAX measure?

A No, DAX can only create calculations or filtered views

B Yes, DAX can delete rows

C Yes, but only for numeric columns

D No, DAX is only for visuals

DAX cannot delete rows but can create tables or measures that show unique values.

Why is removing duplicates important in Power BI?

A To ensure data accuracy and avoid double counting

B To reduce file size only

C To change data types

D To create new columns

Removing duplicates helps keep data accurate and prevents errors in analysis.

Explain how to remove duplicates from a dataset in Power BI using Power Query.

Think about the steps you take to clean data before analysis.

Describe the difference between removing duplicates in Power Query and handling duplicates with DAX.

Consider the roles of Power Query and DAX in Power BI.