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 need to prepare data from a folder containing multiple CSV files with identical structure. What is the most efficient way to load all files into a single table?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use the 'From Folder' data source and then click 'Combine & Transform Data'
Option B is correct because the 'From Folder' data source in Power Query automatically detects multiple CSV files with identical structure and provides a 'Combine & Transform Data' button that merges them into a single table in one step. This is the most efficient method as it eliminates the need for manual imports or scripting, leveraging Power Query's built-in file combination logic.
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.
✗
Import each CSV file separately and then append them
Why it's wrong here
This is time-consuming and not efficient.
✓
Use the 'From Folder' data source and then click 'Combine & Transform Data'
Why this is correct
This automatically combines all files into one table.
Related concept
Read the scenario before looking for a memorised answer.
✗
Write a Python script in Power Query to read and combine files
Why it's wrong here
Python is not natively supported in Power Query.
✗
Use a dataflow to connect to the folder and apply the 'Combine Files' transformation
Why it's wrong here
This is similar to option B but dataflow is not necessary; Desktop can do it.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may think manual appending (Option A) is simpler or that Python scripting (Option C) is a valid Power Query feature, but the exam tests knowledge of Power Query's native 'Combine Files' functionality as the most efficient and integrated method.
Trap categories for this question
Similar concept trap
This is similar to option B but dataflow is not necessary; Desktop can do it.
Detailed technical explanation
How to think about this question
When you use 'From Folder', Power Query reads the folder metadata and then applies the 'Combine Files' transformation, which uses a sample file to infer the schema and then applies the same parsing logic to all files, handling variations in column order or data types via the 'Combine Files' dialog. Under the hood, Power Query generates an M expression that uses `Folder.Files` and `Csv.Document` functions with a `Table.Combine` step, ensuring efficient streaming of large datasets without loading all files into memory at once.
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 the 'From Folder' data source and then click 'Combine & Transform Data' — Option B is correct because the 'From Folder' data source in Power Query automatically detects multiple CSV files with identical structure and provides a 'Combine & Transform Data' button that merges them into a single table in one step. This is the most efficient method as it eliminates the need for manual imports or scripting, leveraging Power Query's built-in file combination logic.
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.
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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