This post is a part of the PL-300: Microsoft Power BI Data Analyst Exam Prep Hub; and this topic falls under these sections:
Prepare the data (25–30%)
   --> Transform and load the data
      --> Create and transform columns

Below are 10 practice questions (with answers and explanations) for this topic of the exam.
There are also 2 practice tests for the PL-300 exam with 60 questions each (with answers) available on the hub.

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Practice Questions

1. Choosing the Correct Tool

You need to split a column named FullName into FirstName and LastName before loading the data into the model. What is the BEST approach?

A. Create two DAX calculated columns
B. Use Split Column in Power Query
C. Use a measure
D. Use a visual-level calculation

Correct Answer: B

Explanation:
Structural changes like splitting columns should be done in Power Query before the data loads into the model.

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2. Fixing Inconsistent Text Data

A column contains values with inconsistent casing (e.g., “north”, “North”, “NORTH”). What transformation should you apply?

A. Replace values
B. Trim
C. Format → Uppercase
D. Conditional column

Correct Answer: C

Explanation:
Formatting text to Uppercase (or Lowercase) standardizes values efficiently and avoids manual replacements.

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3. Extracting Date Components

You need a column containing only the year from an existing Date column. What is the BEST option?

A. Create a DAX measure
B. Extract → Year in Power Query
C. Convert the date to text
D. Use a conditional column

Correct Answer: B

Explanation:
Power Query provides built-in Extract options for date components such as Year, Month, and Day.

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4. Creating Business Logic Columns

You want to classify sales as “High” when the amount is greater than 1,000 and “Low” otherwise. What should you use?

A. Replace values
B. Split column
C. Conditional column
D. Index column

Correct Answer: C

Explanation:
Conditional columns are designed for simple business logic and can be created through the UI without writing code.

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5. Removing Hidden Characters

A text column contains hidden, non-printable characters that affect filtering. Which transformation should you apply?

A. Trim
B. Clean
C. Replace errors
D. Capitalize Each Word

Correct Answer: B

Explanation:
Clean removes non-printable characters that are not visible but can cause data issues.

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6. Merging Text Values into One Column

You need to combine City and State columns into a single column called Location. What should you use?

A. Split Column
B. Replace Values
C. Merge Columns
D. Custom Column

Correct Answer: C

Explanation:
Merge Columns combines multiple columns into one using a specified delimiter.

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7. When to Use a Custom Column

When should you create a Custom Column instead of a Conditional Column?

A. When no logic is required
B. When simple IF/ELSE logic is needed
C. When more complex formulas or functions are required
D. When renaming columns

Correct Answer: C

Explanation:
Custom columns use Power Query M code, allowing more complex logic than conditional columns.

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8. Power Query vs DAX Calculated Columns

Which scenario is BEST suited for a DAX calculated column instead of a Power Query column?

A. Cleaning inconsistent text values
B. Splitting a column by delimiter
C. Creating a column dependent on model relationships
D. Removing leading spaces

Correct Answer: C

Explanation:
DAX calculated columns can reference model relationships, while Power Query columns cannot.

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9. Creating Row Identifiers

You need to add a sequential number to each row to preserve order. What should you use?

A. Conditional column
B. Custom column
C. Index column
D. Replace values

Correct Answer: C

Explanation:
An Index Column assigns a sequential number to each row and is commonly used for sorting or tracking order.

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10. Best Practice for Column Creation

Which is the BEST practice when creating and transforming columns?

A. Create all columns using DAX
B. Transform columns after publishing the report
C. Clean data before creating derived columns
D. Avoid renaming columns

Correct Answer: C

Explanation:
Derived columns should be created from clean, validated data to avoid compounding errors.

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✅ PL-300 Exam Takeaways

• Use Power Query for structural transformations
• Use DAX calculated columns when logic depends on model context
• Know when to split, merge, extract, or derive columns
• Expect scenario-based questions testing tool choice and order of operations

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