DA0-002 Data Acquisition and Preparation Practice Question
A data analyst needs to retrieve all unique job titles from an employees table. Which SQL keyword should be used in the SELECT clause?
⚠ Common exam trap
A common mix-up: candidates confuse the DDL constraint UNIQUE with the DML query keyword DISTINCT — candidates who have seen UNIQUE in CREATE TABLE statements may reflexively choose it for a SELECT query.
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
✓
DISTINCT
The DISTINCT keyword in a SELECT clause eliminates duplicate rows from the result set, returning only unique combinations of the selected columns. When applied to a single column like job_title, it returns each job title exactly once, which is precisely what the analyst needs. DISTINCT operates on the entire row of selected columns, so SELECT DISTINCT job_title FROM employees yields the unique list of titles.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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UNIQUE
Why it's wrong here
UNIQUE is a constraint keyword used in table definitions, not a SELECT-clause modifier. It is tempting because it conveys distinctness, but retrieving unique job titles requires DISTINCT, which operates on the result set rather than enforcing column-level integrity.
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REMOVE DUPLICATES
Why it's wrong here
REMOVE DUPLICATES is not SQL syntax in any dialect; no such keyword exists in the SELECT clause. It is tempting because it describes the intent in plain English, but the language requires DISTINCT to eliminate repeated job title values.
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DISTINCT
Why this is correct
DISTINCT eliminates duplicate rows from the result set, returning only unique job titles as the stem requires. Applied directly in the SELECT clause, it collapses repeated values across the specified column, satisfying the uniqueness constraint without needing GROUP BY or aggregate functions.
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FILTER
Why it's wrong here
FILTER is not a SELECT-clause keyword; it appears in PostgreSQL as a WHERE-like clause on aggregate functions. It is tempting because it restricts rows, but deduplication of job titles requires DISTINCT applied to the selected column.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CompTIA exam blueprint
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.