Join products and products to find engagement score
Last updated: April 28, 2026
Quick Overview
Write a query joining products and products to produce the combined engagement score.
Two Sigma
Data Manipulation (SQL/Python)
Data Scientist
Two Sigma
April 28, 2026Data Scientist
Onsite
Data Manipulation (SQL/Python)
Easy
9
4
4,166 solved
Write a query joining products and products to produce the combined engagement score.
Two Sigma asks this during the Onsite because data engineering skills are critical for the role. You should be comfortable with complex joins, window functions, CTEs, and performance optimization.
What the Interviewer Expects
- Write syntactically correct SQL with proper JOIN and WHERE clauses
- Use GROUP BY and aggregate functions appropriately
- Handle NULL values correctly in your queries
- Explain the query execution plan at a high level
Key Topics to Cover
Window functions (ROW_NUMBER, RANK, LAG, LEAD)
NULL handling and COALESCE
Aggregate functions and GROUP BY
Subqueries and correlated subqueries
Data cleaning and transformation
Common Table Expressions (CTEs)
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 optimize this query for a table with 100 million rows?
- What would you do if this query needs to run every 5 minutes?
- What indexes would you create to support this query?
- Can you rewrite this without using subqueries?
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Practice SQL ProblemsSample Answer
Problem Understanding
The task is to join two tables, products and engagements, to compute a combined engagement score. The products table holds product details such as product_id, product_name, and possibly othe...
Approach
- Identify Tables: Start by identifying the necessary tables:
productsandengagements. - Join Tables: Use an INNER JOIN to connect the two tables on
product_idto filter out products ...
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