AI & Data
Data Engineer Practice Test
20 multiple choice questions for data engineers: SQL, Python, pipelines, warehouses, orchestration, data quality and streaming.
- Questions
- 20
- Time
- 20 min
- Pass mark
- 60%
No account or email needed.
About this test
This test is built around the Data Engineer role. It covers SQL and Python plus the ideas behind reliable pipelines: how warehouses are modelled, how to load data safely, how orchestration works and how to catch bad data early.
It is practice only and is not part of any job application.
What it covers
The question set has 24 questions: 14 easy, 10 medium and 0 hard. Each attempt draws 20 of them at random, so a second try is not the same test.
- Data pipelines (9)
- Python (3)
- SQL (8)
- Warehousing (4)
Try a few sample questions
These are real questions from the set, with the answers and a short explanation. Read the question, decide, then open it to check.
Sample 1 · SQL · easyWhich clause filters individual rows before they are grouped?Show the answer
- HAVING
- WHERECorrect
- GROUP BY
- ORDER BY
WHERE filters rows before grouping. HAVING filters the groups afterwards.
Sample 2 · Python · easyWhich of these Python types is immutable?Show the answer
- list
- dict
- tupleCorrect
- set
A tuple cannot be changed after it is created. Lists, dictionaries and sets can.
Sample 3 · Data pipelines · mediumWhat is the difference between ETL and ELT?Show the answer
- None
- ETL transforms data before loading it, ELT loads raw data first and transforms it inside the warehouseCorrect
- ELT transforms data before loading
- ETL only works with files
ELT is common with modern cloud warehouses that can transform large data cheaply.
How it works
- 20 multiple choice questions, drawn at random from a larger set.
- 20 minutes on the clock. The test submits itself when time runs out.
- Pass mark: 60%.
- No marks are taken off for wrong answers, so answer every question.
- Some questions have more than one correct answer. You must pick all of them to score.
- When you finish you see your score, the correct answers and a short explanation for each.
- Your answers save as you go, so a dropped connection will not lose your work.
- Please stay on the test page. Switching to another tab or window is recorded and you will see a warning.
- Copying text, printing and screenshots are not allowed during the test.
This role is open
This test is built around the Data Engineer role on our jobs board. Taking it is not part of the application.
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