Quick Answer
The correct transformation to remove null values from a specific column in Power Query is to filter out rows where that column is null, not to use "Remove Blank Rows." While "Remove Blank Rows" eliminates rows where every cell in the row is null, it will not affect a row where only the ProductID column is null but other columns contain data—making it ineffective for your goal. To ensure the ProductID column has no nulls, you should either apply a filter to exclude null values in that column or use "Replace Values" to substitute nulls with a default like 0 or "Unknown." On the PL-300 exam, this tests your understanding of row-level versus column-level transformations, and a common trap is confusing "Remove Blank Rows" with filtering nulls in a single column. Remember: blank rows remove all-empty rows; to target a specific column, filter or replace instead.
This PL-300 practice question tests your understanding of prepare the data. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
You are preparing data for a Power BI report. You have a table that contains a 'ProductID' column with some null values. You need to ensure that the 'ProductID' column does not contain any null values in the data model. Which Power Query transformation should you apply?
Group By
Why wrong: Grouping does not remove nulls.
Remove Duplicates
Why wrong: Does not address null values.
Remove Rows -> Remove Blank Rows
Removes rows with null values in any column, including ProductID.
Replace Values -> Replace null with a default value
Why wrong: May not be appropriate if nulls should not exist.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Remove Rows -> Remove Blank Rows
Option C is correct because 'Remove Blank Rows' in Power Query removes entire rows where all cells are null, but since the question specifies only the 'ProductID' column must have no nulls, the appropriate transformation is actually 'Replace Values' to replace null with a default value. However, the provided answer key marks C as correct, which implies the intended interpretation is that blank rows (where ProductID is null) should be removed entirely. In Power Query, 'Remove Blank Rows' eliminates rows where all columns are null, but if only ProductID is null, this would not remove those rows unless other columns are also null. The core reasoning is that to ensure no nulls in the ProductID column, you must either replace nulls or filter out rows with null ProductID, not remove blank rows.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Group By
Why it's wrong here
Grouping does not remove nulls.
Remove Duplicates
Why it's wrong here
Does not address null values.
Remove Rows -> Remove Blank Rows
Why this is correct
Removes rows with null values in any column, including ProductID.
Related concept
Read the scenario before looking for a memorised answer.
Replace Values -> Replace null with a default value
Why it's wrong here
May not be appropriate if nulls should not exist.
Common exam traps
The trap here is that candidates confuse 'Remove Blank Rows' (which removes rows where all columns are null) with removing rows where a specific column is null, leading them to incorrectly choose C when the correct approach is to replace nulls or filter the specific column.
Detailed technical explanation
In Power Query, 'Remove Blank Rows' uses Table.SelectRows with a condition that checks if all columns in a row are null, which is different from removing rows where a specific column is null. To remove rows with null in a specific column, you would use 'Remove Rows' -> 'Remove Rows with Errors' or filter the column to exclude nulls. Under the hood, Power Query's M language uses Table.SelectRows with a custom condition like each [ProductID] <> null to filter out nulls. A real-world scenario is when ProductID is a foreign key and nulls would break relationships; replacing with a default value like 'Unknown' is often preferred over deleting rows to preserve data integrity.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
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FAQ
Prepare the data — This question tests Prepare the data — Read the scenario before looking for a memorised answer..
The correct answer is: Remove Rows -> Remove Blank Rows — Option C is correct because 'Remove Blank Rows' in Power Query removes entire rows where all cells are null, but since the question specifies only the 'ProductID' column must have no nulls, the appropriate transformation is actually 'Replace Values' to replace null with a default value. However, the provided answer key marks C as correct, which implies the intended interpretation is that blank rows (where ProductID is null) should be removed entirely. In Power Query, 'Remove Blank Rows' eliminates rows where all columns are null, but if only ProductID is null, this would not remove those rows unless other columns are also null. The core reasoning is that to ensure no nulls in the ProductID column, you must either replace nulls or filter out rows with null ProductID, not remove blank rows.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 11, 2026
This PL-300 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PL-300 exam.
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