The answer is that the FILTER function removes rows where Quantity <= 10 from the entire Sales table, so those combinations have no data to aggregate. This occurs because FILTER, when used as a table filter argument inside SUMMARIZECOLUMNS, applies a row-level filter to the entire base table before any grouping or aggregation takes place. If a specific ProductID/Region combination only contains rows where Quantity is 10 or less, those rows are entirely eliminated, leaving nothing for the TotalSales measure to sum, resulting in a blank. On the Microsoft Power BI Data Analyst PL-300 exam, this tests your understanding of filter context versus row context, and it is a common trap where candidates mistakenly think the filter applies only after grouping. Remember the memory tip: "FILTER first, then group"—the filter strips rows from the table before SUMMARIZECOLUMNS ever sees them, so blanks appear when no qualifying rows remain for a given combination.
PL-300 Prepare the data Practice Question
This PL-300 practice question tests your understanding of prepare the data. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.
Exhibit
Refer to the exhibit.
```dax
EVALUATE
SUMMARIZECOLUMNS(
'Sales'[ProductID],
'Sales'[Region],
FILTER('Sales', 'Sales'[Quantity] > 10),
"TotalSales", SUM('Sales'[Amount])
)
```
You are troubleshooting a Power BI report that uses a DAX query to summarize sales data. The query returns rows but the TotalSales column shows blank for some ProductID/Region combinations. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The FILTER function removes rows where Quantity <= 10 from the entire Sales table, so those combinations have no data to aggregate.
Option D is correct because the FILTER function in DAX, when used as a table filter argument in SUMMARIZECOLUMNS, applies a row-level filter to the entire Sales table before aggregation. If Quantity <= 10 for a given ProductID/Region combination, all rows for that combination are removed, leaving no data to aggregate, which results in a blank TotalSales. This is a common cause of unexpected blanks when using FILTER inside SUMMARIZECOLUMNS.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
The syntax of SUMMARIZECOLUMNS is incorrect; it should use ADDCOLUMNS.
Why it's wrong here
The syntax is valid.
✗
The filter condition is applied after aggregation, so it cannot filter out rows.
Why it's wrong here
FILTER is applied before aggregation.
✗
The relationships between tables are missing, causing blank values.
Why it's wrong here
SUMMARIZECOLUMNS works on a single table.
✓
The FILTER function removes rows where Quantity <= 10 from the entire Sales table, so those combinations have no data to aggregate.
Why this is correct
FILTER is applied as a table filter, not a row filter within groups.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume FILTER only affects the measure calculation, not the row context of the entire table, leading them to overlook that FILTER removes rows before aggregation, causing blanks for filtered-out combinations.
Detailed technical explanation
How to think about this question
Under the hood, SUMMARIZECOLUMNS applies all table filters (including FILTER) to the base table before performing grouping and aggregation. This is different from CALCULATETABLE, which applies filter context after evaluation. A subtle behavior: if FILTER is used on a column that is not part of the grouping columns, it can still remove entire rows from the aggregation, leading to blanks for combinations that would otherwise have data. In real-world scenarios, this often occurs when a report designer intends to filter only the measure but inadvertently filters the entire table.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
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
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Prepare the data — This question tests Prepare the data — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The FILTER function removes rows where Quantity <= 10 from the entire Sales table, so those combinations have no data to aggregate. — Option D is correct because the FILTER function in DAX, when used as a table filter argument in SUMMARIZECOLUMNS, applies a row-level filter to the entire Sales table before aggregation. If Quantity <= 10 for a given ProductID/Region combination, all rows for that combination are removed, leaving no data to aggregate, which results in a blank TotalSales. This is a common cause of unexpected blanks when using FILTER inside SUMMARIZECOLUMNS.
What should I do if I get this PL-300 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.