Quick Answer
The correct approach is to use a staging table with the COPY command and then MERGE into the target table, because Redshift’s COPY command does not have a built-in `REMOVEDUPLICATES` option. Instead, you load raw data into a temporary staging table via COPY, which efficiently ingests the CSV from S3, and then apply a MERGE operation (also known as an upsert) to insert only unique rows into the final target table while discarding or updating duplicates based on a primary key. On the AWS Certified Data Engineer Associate DEA-C01 exam, this question tests your understanding that COPY is a bulk-load tool, not a deduplication engine, and that handling duplicates requires a two-step pattern. A common trap is assuming a `REMOVEDUPLICATES` flag exists in COPY, but it does not—Redshift relies on staging tables and MERGE for clean, duplicate-free loads. Memory tip: “COPY to stage, MERGE to purge.”
This DEA-C01 practice question tests your understanding of data ingestion and transformation. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company needs to ingest data from Amazon S3 into Amazon Redshift for analytics. The data arrives in CSV format with headers and may contain duplicate rows. Which Redshift command should be used to load the data while handling duplicates?
COPY command with the `REMOVEDUPLICATES` option
Why wrong: No such option in COPY.
INSERT INTO ... SELECT DISTINCT from S3 via Spectrum
Why wrong: Spectrum queries external data but not optimal for loading.
Use a staging table with COPY and then MERGE into the target table
MERGE allows handling duplicates.
CREATE TABLE AS SELECT DISTINCT from the S3 bucket
Why wrong: Not a direct load command.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Use a staging table with COPY and then MERGE into the target table
Option B is correct because the `COPY` command with the `REMOVEDUPLICATES` option is not valid; the correct approach is to use a staging table and then use `MERGE` (or `UPSERT`) to handle duplicates. Option A (COPY) alone does not remove duplicates. Option C (INSERT INTO SELECT) does not handle duplicates. Option D (CREATE TABLE AS) does not handle duplicates.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
COPY command with the `REMOVEDUPLICATES` option
Why it's wrong here
No such option in COPY.
INSERT INTO ... SELECT DISTINCT from S3 via Spectrum
Why it's wrong here
Spectrum queries external data but not optimal for loading.
Use a staging table with COPY and then MERGE into the target table
Why this is correct
MERGE allows handling duplicates.
Related concept
Read the scenario before looking for a memorised answer.
CREATE TABLE AS SELECT DISTINCT from the S3 bucket
Why it's wrong here
Not a direct load command.
Common exam traps
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Trap categories for this question
Command / output trap
Not a direct load command.
Detailed technical explanation
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Identify which DEA-C01 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Data Ingestion and Transformation — study guide chapter
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FAQ
Data Ingestion and Transformation — This question tests Data Ingestion and Transformation — Read the scenario before looking for a memorised answer..
The correct answer is: Use a staging table with COPY and then MERGE into the target table — Option B is correct because the `COPY` command with the `REMOVEDUPLICATES` option is not valid; the correct approach is to use a staging table and then use `MERGE` (or `UPSERT`) to handle duplicates. Option A (COPY) alone does not remove duplicates. Option C (INSERT INTO SELECT) does not handle duplicates. Option D (CREATE TABLE AS) does not handle duplicates.
Identify which DEA-C01 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 20, 2026
This DEA-C01 practice question is part of Courseiva's free Amazon Web Services 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 DEA-C01 exam.
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