Join users and clicks to find engagement score
Last updated: August 10, 2025
Quick Overview
Write a query joining users and users to produce the combined engagement score.
Netflix
Data Manipulation (SQL/Python)
Data Scientist
Netflix
August 10, 2025Data Scientist
Take-home Project
Data Manipulation (SQL/Python)
Medium
87
7
4,421 solved
Write a query joining users and users to produce the combined engagement score.
Data manipulation questions at Netflix test your ability to work with real-world datasets. This Take-home Project question evaluates your SQL proficiency, understanding of data modeling, and ability to derive insights from raw data.
What the Interviewer Expects
- Use advanced SQL features: window functions, CTEs, subqueries
- Write efficient queries that avoid common performance pitfalls
- Handle complex data transformations with multiple joins and aggregations
- Discuss indexing strategy and query optimization
- Address data quality issues: duplicates, missing values, outliers
Key Topics to Cover
Pandas vectorized operations and groupby
Subqueries and correlated subqueries
Window functions (ROW_NUMBER, RANK, LAG, LEAD)
Data cleaning and transformation
How to Approach This
- Clarify the schema and expected output format before writing queries.
- Use CTEs (WITH clauses) to break complex queries into readable steps.
- Consider window functions (ROW_NUMBER, RANK, LAG, LEAD) for ranking and sequential analysis.
- Watch for NULLs, duplicates, and edge cases in JOINs and GROUP BY.
- For pandas, prefer vectorized operations over row-by-row iteration.
Possible Follow-up Questions
- How would you handle slowly changing dimensions in this scenario?
- How would you optimize this query for a table with 100 million rows?
- How would you validate the correctness of your query results?
- Can you rewrite this without using subqueries?
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Practice SQL ProblemsSample Answer
Problem Understanding
In this problem, we have two tables: users and clicks. The users table contains information about each user, including their unique user_id. The clicks table records each click event with a ...
Approach
- Join the Tables: Start by performing an inner join between the
usersandclickstables on theuser_id. This will give us a dataset that includes user details alongside their click events....
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