Join orders and users to find time to first action
Last updated: January 16, 2026
Quick Overview
Write a query joining orders and impressions to produce the combined time to first action.
Jane Street
January 16, 20261
7
379 solved
Write a query joining orders and impressions to produce the combined time to first action.
Data manipulation questions at Jane Street test your ability to work with real-world datasets. This Onsite question evaluates your SQL proficiency, understanding of data modeling, and ability to derive insights from raw data.
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
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 validate the correctness of your query results?
- How would you optimize this query for a table with 100 million rows?
- How would you handle slowly changing dimensions in this scenario?
Sharpen Your Skills on Codemia
Practice similar problems with our interactive workspace, get AI feedback, and track your progress.
Practice SQL ProblemsSample Answer
Problem Understanding
In this problem, we have two datasets: orders and impressions. The orders table contains information about user orders, including fields like user_id, order_time, and order_id. The `impres...
Approach
- Identify the Relevant Columns: We need
user_id,impression_time, andorder_timefrom their respective tables. - Determine the First Actions: Use aggregate functions to find the min...
Submit Your Answer
