DA0-002 Data Acquisition and Preparation Practice Question
During data profiling, an analyst wants to identify the number of distinct values in a column. Which SQL function should be used?
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
✓
COUNT(DISTINCT column)
COUNT(DISTINCT column) returns the number of unique non-null values.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
DISTINCT(column)
Why it's wrong here
DISTINCT is not a function.
- ✓
COUNT(DISTINCT column)
Why this is correct
Returns distinct count.
- ✗
COUNT(*)
Why it's wrong here
COUNT(*) counts all rows.
- ✗
COUNT(column)
Why it's wrong here
COUNT(column) counts non-null rows.
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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.