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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 1–30 of 446 results

  • AdobeMediumSoftware Engineer
    Find Top-Funded Villages and Their Top Projects

    Tests the ability to write a multi-level SQL aggregation with window functions, exact date filtering, tie handling, and deterministic sorting.

    Data Manipulation (SQL/Python)Online Assessmentsqlwindow-functionsaggregation
  • AdobeMediumSoftware Engineer
    Implement scalable word count locally

    This question evaluates understanding of scalable word-count processing, including tokenization and normalization rules, streaming or external-memory techniques for inputs larger than RAM, and efficient top‑K frequency computation.

    Data Manipulation (SQL/Python)Technical Screen
  • AdobeMediumData Scientist
    Solve SQL and Python Data Manipulation Tasks

    This question evaluates proficiency in SQL event-log aggregation and basic Python data-structure transformations, assessing competencies such as counting distinct users, identifying frequent event types, and performing dictionary/list/string manipulations.

    Data Manipulation (SQL/Python)Onsite
  • AeoneaMediumSoftware Engineer
    Fill missing values with means

    This question evaluates proficiency in missing-data imputation and pandas DataFrame manipulation, testing skills in column-wise aggregation, group-wise operations, and edge-case handling within the Data Manipulation (SQL/Python) domain.

    Data Manipulation (SQL/Python)Technical Screen
  • AffirmMediumData Scientist
    Analyze Loan Payments Using Pandas for Key Insights

    This question evaluates data manipulation and aggregation skills using pandas, focusing on computing per-loan payment totals, payment success rates, and a repayment-status flag. It is commonly asked to assess applied data wrangling and numeric summarization abilities in the Data Manipulation (SQL/Python) domain, testing practical application rather than purely conceptual understanding.

    Data Manipulation (SQL/Python)Technical Screen
  • AffirmMediumSoftware Engineer
    Analyze Returning Borrowers Across Two Days of Logs

    Process two daily loan activity logs to identify users active on both days with diverse loan types, then score them using a configurable trust policy.

    Data Manipulation (SQL/Python)Technical ScreenData ManipulationHash TablePython
  • AffirmMediumSoftware Engineer
    Implement and debug event filtering in Python

    This question evaluates proficiency in data manipulation and algorithmic reasoning in Python, covering event filtering, stable sorting, deduplication by identifier, timestamp windowing, and analysis of time and space complexity.

    Data Manipulation (SQL/Python)Onsite
  • AgodaEasyData Engineer
    Find the Longest Calendar-Day Streak with All Employees Present

    Identify dates when every employee is present and compute the longest consecutive streak, treating missing attendance as a gap.

    Data Manipulation (SQL/Python)Technical Screen
  • AgodaEasyData Engineer
    Rank Customers by Monthly Revenue with Competition Ties

    Aggregate customer revenue by month and return top competition ranks, preserving tied totals and deterministic display order.

    Data Manipulation (SQL/Python)Technical Screen
  • AgodaEasyData Engineer
    Return Every Employee with a Mapped or Default Unique ID

    Join employees to unique-ID mappings while preserving unmatched employees and applying an explicit fallback identifier.

    Data Manipulation (SQL/Python)Technical Screen
  • AirbnbMediumData Scientist
    Aggregate User Activity, Fit Regression, Interpret Coefficients

    This question evaluates skills in relational data aggregation and feature engineering using SQL alongside fitting and interpreting regression models in Python, targeting competencies in transforming event-level user metrics into a modeling dataset and interpreting coefficient estimates.

    Data Manipulation (SQL/Python)Technical Screen
  • AirbnbMediumData Scientist
    Build panel in SQL; run causal regression

    This question evaluates proficiency in SQL-based panel data construction, time-series aggregation and rolling-window metrics together with applied causal inference in Python, including two-way fixed-effects difference-in-differences, clustered standard errors, lead tests, and count-model re-specification; it targets Data Manipulation (SQL/Python) skills relevant for Data Scientist roles. It is commonly asked because it combines practical implementation and conceptual understanding—testing temporal joins, treatment timing, avoidance of lookahead/immortal-time biases and late-adopter issues, interpretation of interaction coefficients and confidence intervals, and the ability to reason about identification and model choice.

    Data Manipulation (SQL/Python)Technical Screen
  • AirbnbMediumData Engineer
    Calculate the Median House Price in Each City

    Tests your ability to compute grouped medians in PostgreSQL, properly handling even and odd row counts, duplicate price values, and numeric precision.

    Data Manipulation (SQL/Python)Onsitesqlpostgresqlaggregations
  • AirbnbMediumData Scientist
    Compute C/T metrics from bookings and visits

    This question evaluates time-window attribution, visit deduplication, control vs treatment metric computation, aggregation of conversions and revenue, and statistical interval estimation (Wilson CIs), testing practical data manipulation skills with SQL or Python in the Data Manipulation (SQL/Python) domain.

    Data Manipulation (SQL/Python)Technical Screen
  • AirbnbMediumData Scientist
    Compute browsing metrics in Python from logs

    This question evaluates a candidate's ability to perform event-level data manipulation and analytics in Python and SQL, covering sessionization, time-zone–consistent timestamp handling, deduplication, funnel construction, segment-level aggregation, conversion-rate computation, and statistical confidence intervals such as the Wilson CI.

    Data Manipulation (SQL/Python)Technical Screen
  • AirbnbMediumData Scientist
    Describe How You Use SQL in Data Science Work

    This question assesses a candidate's ability to articulate their technical workflow in SQL, focusing on data extraction strategies, quality assurance, and how technical analysis translates into business impact.

    Data Manipulation (SQL/Python)HR ScreenSQLData ScienceAnalytics
  • AirbnbMediumData Engineer
    Estimate Page-Visit Duration from the Next User Event

    Implement logic to compute user page-visit durations based on adjacent event timestamps, deterministically resolving ties and handling boundary conditions for terminal events.

    Data Manipulation (SQL/Python)Onsitepythonsqldata-manipulation
  • AirbnbMediumData Engineer
    Find Hosts Meeting Listing, Rating, and Review-Coverage Rules

    Tests the ability to write a SQL query performing multi-table aggregations, date-windowed conditional logic, and host-level qualification filtering across listing counts, average ratings, and recent review coverage.

    Data Manipulation (SQL/Python)Onsitesqlaggregationconditional-logic
  • AirbnbMediumData Engineer
    Find Users with Seven Consecutive Impression Days

    Tests your ability to identify consecutive calendar-day activity streaks in PostgreSQL using window functions, date arithmetic, and deduplication.

    Data Manipulation (SQL/Python)Onsitesqlpostgresqlwindow-functions
  • AirbnbMediumSoftware Engineer
    Review a geospatial Python module

    This question evaluates proficiency in geospatial data processing and Python code review, including detection of correctness bugs, numerical stability issues, CRS handling, performance optimization, refactoring, testing strategy, and security considerations when working with CSV/GeoJSON datasets.

    Data Manipulation (SQL/Python)Technical Screen
  • AirwallexMediumData Scientist
    Compute Moderation View Metrics

    An Airwallex Data Scientist onsite SQL question on content-moderation analytics. You write three queries over a per-day view table and a one-to-many post/violation-type policy-score table: distinct posts with 10+ views in the last 7 days, Nudity view prevalence over the last 30 days, and a monthly violation-type distribution. The core challenge is windowed aggregation plus avoiding view double-counting across violation types.

    Data Manipulation (SQL/Python)Onsite
  • Akuna CapitalMediumSoftware Engineer
    Answer SQL MCQs with reasoning

    This question evaluates proficiency in SQL query semantics and reasoning about relational operations—specifically INNER, LEFT, and RIGHT JOIN behavior; GROUP BY and HAVING usage; NULL handling in comparisons and aggregates; window functions such as ROW_NUMBER and RANK; and the logical query processing order—within the Data Manipulation (SQL/Python) domain. It is commonly asked to assess the ability to interpret and justify query outcomes versus alternative answers, testing both conceptual understanding of relational theory and practical application of SQL query behavior.

    Data Manipulation (SQL/Python)Online Assessment
  • Akuna CapitalMediumSoftware Engineer
    Evaluate SQL expressions for zero

    This question evaluates understanding of SQL type coercion, boolean semantics, comparison operators, and dialect-specific evaluation behavior (for example, MySQL), focusing on interpreting expressions that may evaluate to zero.

    Data Manipulation (SQL/Python)Online Assessment
  • AmazonMediumBusiness Intelligence Engineer
    Analyze Seller Compliance and Customer Purchase Patterns

    This question evaluates a candidate's ability to manipulate and analyze temporal and categorical datasets, covering competencies such as event sequencing, set-based filtering, and cross-table aggregation in SQL/Python.

    Data Manipulation (SQL/Python)Onsite
  • AmazonMediumData Scientist
    Analyze Top 10 Items' Revenue Contribution by Category

    This question evaluates proficiency in data manipulation and analytical querying—aggregation, window functions, ranking and revenue attribution—alongside conceptual knowledge of normalization versus denormalization and ETL pipeline design.

    Data Manipulation (SQL/Python)Onsite
  • AmazonMediumData Scientist
    Append country tables and rank salaries in USD

    This question evaluates skills in data manipulation and integration, specifically appending country-level tables, normalizing salaries via historical exchange rates, deduplicating by a composite primary key, and ranking results, with implementations expected in both SQL and pandas.

    Data Manipulation (SQL/Python)Technical Screen
  • AmazonMediumData Scientist
    Build DID panel and compute effects in SQL

    This question evaluates proficiency in panel data construction and causal inference workflows, specifically difference-in-differences estimation, SQL aggregation for user-week metrics, and propensity-score matching implemented in Python.

    Data Manipulation (SQL/Python)HR Screen
  • AmazonMediumData Scientist
    Build DiD dataset with SQL

    This question evaluates proficiency in SQL-based data manipulation and panel construction for staggered-adoption difference-in-differences, testing skills in handling adoption dates, event-time calculations, boundary conditions, and aggregation in the Data Manipulation (SQL/Python) domain.

    Data Manipulation (SQL/Python)Technical Screen
  • AmazonMediumData Scientist
    Calculate Defect Rate and Identify Top Lanes for Carriers

    This question evaluates competency in SQL-based data manipulation for a data scientist role, covering joins, aggregations, date-based filtering, metric computation, and use of window functions to derive week-over-week changes.

    Data Manipulation (SQL/Python)Technical Screen
  • AmazonMediumData Scientist
    Calculate Monthly Revenue from Orders in 2023

    This question evaluates proficiency in SQL-based data manipulation, including aggregation, date extraction, and combining transactional tables to produce business metrics, and falls under the Data Manipulation (SQL/Python) domain.

    Data Manipulation (SQL/Python)Technical Screen