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Data Manipulation (SQL/Python) Interview Questions

Practice 9403 coding, system design and machine learning questions from 546 companies, sorted by role, topic and interview round. Every question has step-by-step hints, a code runner that supports 8 languages and an AI mentor; members also get the full solution walkthrough.

9403
Questions
546
Companies
11
Topics
8
Languages

Showing 31–39 of 39 results

  • TikTokMediumData Scientist
    Select max-discount product per category

    This question evaluates proficiency in data manipulation and SQL querying—specifically use of window functions versus set-based alternatives, group-level ranking and tie-breaking, NULL-aware expressions, and numeric precision when computing discounts within the Data Manipulation (SQL/Python) domain.

    Data Manipulation (SQL/Python)Online Assessment
  • Two SigmaMediumData Scientist
    Analyze NYC taxi trips efficiently over last 7 days

    This question evaluates proficiency in time-series filtering, relational joins, grouped aggregations (median and high-percentile calculations), numeric stability of percentile methods, and performance-aware vectorized data manipulation using SQL or pandas.

    Data Manipulation (SQL/Python)Online Assessment
  • VisaMediumSoftware Engineer I
    Query the Top Ten Customers by Recent Spend

    This problem tests proficiency in SQL aggregation, window functions, and joining across normalized transactional tables to perform time-bound analysis.

    Data Manipulation (SQL/Python)Online AssessmentSQLAggregationJoins
  • WayfairEasyData Scientist
    Clean scores and return top 5 students

    This problem tests your ability to clean tabular data by performing conditional imputation and applying window functions to rank performance metrics.

    Data Manipulation (SQL/Python)Online AssessmentPandasData CleaningImputation
  • WayfairEasyData Scientist
    Find top buyer in earliest 10-year window

    This question tests the ability to filter data by date ranges, group transactional records by user, and use window functions or aggregations to identify a specific record based on criteria.

    Data Manipulation (SQL/Python)Online AssessmentSQLAggregationWindow Functions
  • WayfairEasyData Scientist
    Solve SQL and Python OA tasks

    This question evaluates SQL and pandas data-manipulation skills, including joined aggregations over date windows, handling of missing values with median imputation, and multi-criteria sorting and tie-breaking.

    Data Manipulation (SQL/Python)Online Assessment
  • WaymoMediumData Scientist
    Analyze User Ride Activity with SQL

    Solve four SQL analytics tasks on ride and user tables: inactive users, monthly rides and ratings, low-frequency users by city, and first-versus-third active-month ratings. The walkthrough emphasizes outer joins, date boundaries, aggregation grain, window functions, and weighted averages.

    Data Manipulation (SQL/Python)Online Assessment
  • WaymoMediumData Scientist
    Compute Ride Metrics in SQL

    This question evaluates SQL data manipulation skills, covering joins between normalized tables, timezone-aware date filtering and calendar-month grouping, aggregation and NULL-aware averages, counting distinct and inactive users, and cohort/retention analysis.

    Data Manipulation (SQL/Python)Online Assessment
  • WaymoMediumData Scientist
    Implement a Safe Average Function in Python

    Implement a Python average function that returns zero for an empty list and explain its time and space complexity. Clarify numeric types, missing values, NaN behavior, streaming alternatives, precision concerns, and the tests needed for a reliable data utility.

    Data Manipulation (SQL/Python)Online Assessment