The correct answer is to use Power Query's Combine Files feature, selecting a sample file and promoting headers, then transforming column names to a standard set. This is the best practice because Power Query uses the sample file to infer the transformation logic—such as promoting the first row to headers—and then applies that exact logic to all 100 Excel files in the SharePoint folder. By standardizing the column names within the sample file step, you ensure consistent schema across all files, which preserves data integrity when combining them into a single table. On the PL-300 exam, this scenario tests your understanding of Power Query’s M-engine and its ability to handle heterogeneous data sources, a common trap being to manually merge each file or rely on a folder connector without a sample file. Remember the memory tip: “Sample first, standardize second”—always pick one representative file to define your column transformations before combining the rest.
PL-300 Prepare the data Practice Question
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 connecting to a SharePoint folder containing 100 Excel files. Each file has a similar structure but different column names. What is the best practice to combine these files into a single table while preserving the data?
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.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use Power Query's 'Combine Files' feature, selecting a sample file and promoting headers, then transforming column names to a standard set.
Option A is correct because Power Query's 'Combine Files' feature is designed specifically for this scenario: it uses a sample file to infer the transformation logic (e.g., promoting headers), then applies that logic to all files in the folder. By transforming column names to a standard set within the sample file step, you ensure consistent column names across all files, preserving data integrity while combining them into a single table.
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.
✓
Use Power Query's 'Combine Files' feature, selecting a sample file and promoting headers, then transforming column names to a standard set.
Why this is correct
This automates combining files with different structures.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Load each file as a separate table and create relationships in the model.
Why it's wrong here
This creates multiple tables, not a single combined table.
✗
Use Power Query's 'Merge Queries' to join all files into one table.
Why it's wrong here
Merge is for combining columns from different tables, not rows from multiple files.
✗
Use 'Append Queries' to stack all files, then rename columns manually.
Why it's wrong here
Append requires identical column names; renaming manually is error-prone.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse 'Combine Files' (which unions multiple files with a consistent transformation) with 'Merge Queries' (which joins tables horizontally) or 'Append Queries' (which stacks tables but lacks automated column standardization).
Detailed technical explanation
How to think about this question
Under the hood, Power Query's 'Combine Files' uses a 'Transform Sample File' step that generates a function (e.g., 'TransformFile') which is then applied to each file via 'Invoke Custom Function'. This leverages the M language's 'Table.Combine' to union all transformed tables. A subtle behavior is that if column names vary significantly, the sample file's transformation may fail for files with missing columns, requiring additional error handling or a dynamic column detection approach.
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: Use Power Query's 'Combine Files' feature, selecting a sample file and promoting headers, then transforming column names to a standard set. — Option A is correct because Power Query's 'Combine Files' feature is designed specifically for this scenario: it uses a sample file to infer the transformation logic (e.g., promoting headers), then applies that logic to all files in the folder. By transforming column names to a standard set within the sample file step, you ensure consistent column names across all files, preserving data integrity while combining them into a single table.
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: "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.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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