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 have a Power BI dataset that combines sales data from two Excel files: Sales2023.xlsx and Sales2024.xlsx. Both files have the same schema. You need to combine them into a single table without duplicating rows. What is the best approach in Power Query?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "best"
Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
Use Union in DAX.
Why wrong: Union is a DAX function, but not the best approach in Power Query.
Use Group By to summarize data.
Why wrong: Group By aggregates, not combines rows.
Use Append Queries.
Append Queries combines rows from two tables.
Use Merge Queries as a new query.
Why wrong: Merge combines columns, not rows.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Use Append Queries.
Option C is correct because Append Queries in Power Query is specifically designed to combine rows from two or more tables with the same schema into a single table, stacking them vertically without duplicating rows. This operation is performed in the Power Query Editor (M language) and is the standard approach for unioning data from multiple sources during the data preparation phase, before loading into the Power BI data model.
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.
Use Union in DAX.
Why it's wrong here
Union is a DAX function, but not the best approach in Power Query.
Use Group By to summarize data.
Why it's wrong here
Group By aggregates, not combines rows.
Use Append Queries.
Why this is correct
Append Queries combines rows from two tables.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Use Merge Queries as a new query.
Why it's wrong here
Merge combines columns, not rows.
Common exam traps
The trap here is that candidates often confuse Append Queries (vertical stacking) with Merge Queries (horizontal joining), or mistakenly think DAX Union is appropriate for data preparation, when Power Query is the correct tool for this task.
Detailed technical explanation
Under the hood, Append Queries in Power Query uses the M function Table.Combine, which performs a union of rows from multiple tables, automatically matching columns by name (not position). A subtle behavior is that if column names differ between tables, Append Queries will create separate columns for each unique name, potentially introducing nulls; to avoid this, ensure column names are identical. In real-world scenarios, this is commonly used when monthly or yearly sales files have the same structure and need to be combined for time-series analysis.
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: Use Append Queries. — Option C is correct because Append Queries in Power Query is specifically designed to combine rows from two or more tables with the same schema into a single table, stacking them vertically without duplicating rows. This operation is performed in the Power Query Editor (M language) and is the standard approach for unioning data from multiple sources during the data preparation phase, before loading into the Power BI data model.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Yes — watch for: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
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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