PL-300 Prepare the data Practice Question
Which TWO actions can you take in Power Query Editor to improve data quality and reduce load time? (Choose two.)
⚠ Common exam trap
It's easy for candidates to confuse actions that improve data quality (like filtering or promoting headers) with actions that merely reorganize data (like sorting or splitting), leading them to select options that do not actually reduce load time or enhance data integrity.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Filter out empty rows.
Filtering out empty rows in Power Query Editor directly reduces the number of rows loaded into the data model, which decreases memory usage and improves refresh performance. This action also enhances data quality by removing incomplete records that could cause errors in measures or relationships. The other options either do not reduce load time or may increase it.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Split columns by delimiter to create more columns.
Why it's wrong here
Splitting columns increases the number of columns, which can increase load time and memory usage, and does not directly improve data quality or reduce load time.
- ✓
Filter out empty rows.
Why this is correct
Correct. Filtering out empty rows removes unnecessary data, reducing load time and improving data quality by eliminating incomplete records.
- ✗
Sort the data by a key column.
Why it's wrong here
Sorting data does not reduce load time; it may even increase processing time. It also does not improve data quality.
- ✗
Promote headers to use the first row as column names.
Why it's wrong here
Promoting headers improves data quality by correctly labeling columns, but it does not reduce load time as it does not change the volume of data loaded.
- ✗
Merge queries to combine data from multiple sources.
Why it's wrong here
Merging queries combines data from multiple sources, which can increase complexity and load time, and does not inherently reduce load time.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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