DA0-002 Data Acquisition and Preparation Practice Question
You are analyzing sales data and need to calculate the moving average of monthly sales over the previous 3 months for each month. Which type of function is best suited for this task?
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
✓
Window function with OVER()
Window functions, specifically using OVER() with ORDER BY and a frame specification, can compute moving averages. Aggregate functions alone cannot access previous rows without a self-join. String and date functions are irrelevant.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
String function
Why it's wrong here
String functions manipulate text, not numeric calculations across rows.
- ✓
Window function with OVER()
Why this is correct
Window functions operate on a set of rows related to the current row, perfect for moving averages.
- ✗
Aggregate function with GROUP BY
Why it's wrong here
GROUP BY collapses rows and cannot compute moving averages across rows.
- ✗
Date function
Why it's wrong here
Date functions extract date parts, not compute moving aggregates.
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This DA0-002 practice question is part of Courseiva's free CompTIA 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 DA0-002 exam.