DA0-002 Data Analysis Practice Question
Exhibit
SELECT department, COUNT(*) as employee_count FROM employees WHERE hire_year > 2020 GROUP BY department HAVING COUNT(*) > 5;
Refer to the exhibit. Which clause is used to aggregate the data by department?
⚠ Common exam trap
CompTIA often tests the distinction between WHERE (row-level filter) and HAVING (group-level filter), leading candidates to confuse HAVING with GROUP BY when the question asks for the clause that performs aggregation.
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
✓
GROUP BY
The GROUP BY clause is used to aggregate data by department because it groups rows that have the same values in the specified column(s), allowing aggregate functions like SUM, AVG, or COUNT to be applied per group. In SQL, without GROUP BY, aggregate functions would operate on the entire result set, not per department.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
HAVING
Why it's wrong here
HAVING filters groups after GROUP BY has formed them; without GROUP BY present it cannot aggregate by department. It is the correct clause when filtering aggregated results, such as returning only departments whose total sales exceed a threshold.
- ✗
WHERE
Why it's wrong here
WHERE filters individual rows before any grouping occurs, so it cannot aggregate by department. It is the correct clause when restricting which source rows enter the query, such as selecting only records from a specific date range.
- ✗
ORDER BY
Why it's wrong here
ORDER BY sorts the result set after aggregation; it does not group rows, so it cannot aggregate by department. It is the correct clause when the requirement is to sequence output rows, for example listing departments alphabetically or totals descending.
- ✓
GROUP BY
Why this is correct
GROUP BY partitions rows sharing the same department value into groups, enabling aggregate functions such as COUNT, SUM or AVG to be computed per department. It is the clause that performs the grouping the question requires.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.