Coding questions

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1. Coding questions · Meta

   Write SQL to analyze shop visibility

   This question evaluates proficiency in SQL-based time-series and event-data manipulation, including deduplication of consecutive states, window functions, aggregation, cohort analysis, and percentile/summary statistics.

2. Coding questions · DoorDash

   Write SQL to backtest refund policy

   This question evaluates advanced SQL data-manipulation and analytics competency, including time-based lateness calculations, window functions (PERCENT_RANK and rolling/partitioned windows), CTEs and joins, aggregation, and monetary-field handling for a policy-simulation scenario.

3. Coding questions · Meta

   Write SQL to compare exclusive category engagement

   This question evaluates SQL-based data manipulation and cohort analysis competencies, including cohort definition, session-level filtering and aggregation for metrics such as user counts, median active days, proportions, and per-user average minutes while applying data-quality constraints over a fixed date window.

4. Coding questions · Meta

   Write SQL to compare social-only vs game-only engagement

   This question evaluates SQL proficiency in data manipulation tasks such as cohorting, time-window filtering, date/week bucketing, categorical inclusion/exclusion, and computing per-user and per-week engagement metrics.

5. Coding questions · Capital One

   Write SQL to compute campaign net revenue

   This question evaluates SQL-based data manipulation and analytics skills, including aggregation, deduplication, date-range filtering, revenue and cost calculations, and selection logic for prioritizing additional donors.

6. Coding questions · IBM

   Write SQL to compute max and min marks

   This question evaluates a candidate's ability to perform basic data aggregation in SQL, specifically computing summary statistics from a single table. It is commonly asked to assess competence in data manipulation and query result shaping within the Data Manipulation (SQL/Python) domain, focusing on practical application of SQL aggregation rather than purely conceptual theory.

7. Coding questions · Pinterest

   Write SQL to compute max-overlap lists

   This question evaluates proficiency in SQL data manipulation and set-based operations, focusing on deduplication, pairwise aggregation, and similarity metric computation (Jaccard) over relational tables.

8. Coding questions · Meta

   Write SQL to compute shop visibility share

   This question evaluates proficiency in SQL data manipulation and analytical metrics computation, including deduplication, session-level filtering, time-window aggregations, and click-through rate calculations within the Data Manipulation (SQL/Python) domain.

9. Coding questions · Stripe

   Write SQL to detect recurring non-subscription users

   This question evaluates a candidate's ability to perform advanced SQL data manipulation and temporal pattern detection in transactional datasets, including attribute-based matching (amount and card fingerprint) and filtering by transaction status.

10. Coding questions · Capital One

    Write SQL to find top net-revenue products

    This question evaluates proficiency in SQL data manipulation, including joins, aggregations, date-window filtering, handling returns and net-revenue calculations, plus the use of analytic/window functions for per-category ranking and tie-breaking.

11. Coding questions · Meta

    Write SQL to flag coordinated fake accounts

    This question evaluates proficiency in SQL-based data manipulation, temporal windowing, event-table joins, aggregation and feature engineering for fraud detection, including computing weighted risk_score flags across user activity.

12. Coding questions · Roblox

    Write SQL to flag suspect payments and chargebacks

    This question evaluates proficiency with SQL conditional logic (CASE WHEN), JOINs, date/time arithmetic, aggregation, and encoding business rules for flagging suspect payments and chargebacks, and is categorized under Data Manipulation (SQL/Python) for a Data Scientist role.

13. Coding questions · PayPal

    Write SQL to flag Venmo ATO

    This question evaluates a candidate's ability to construct complex SQL to detect account-takeover (ATO) signals in a payments platform, assessing skills in event-time windowing, deduplication, joins across user/login/transaction tables, and categorical flagging of new devices or IPs.

14. Coding questions · Meta

    Write SQL to infer group-call demand

    This question evaluates SQL-based data manipulation and product-analytics competencies, including temporal sessionization, graph connectivity inference for detecting overlapping 1:1 call loops, deduplication trade-offs (UNION vs UNION ALL), and computation of derived metrics to estimate latent feature demand within the Data Manipulation (SQL/Python) domain. It is commonly asked because it measures practical application of event-time windowing, connected-component reasoning and edge-case handling (e.g., excluding failed connections) for producing daily summary metrics, emphasizing hands-on SQL proficiency over purely conceptual understanding.

15. Coding questions · Bilt Rewards

    Write SQL to Join Merchants and Triple Restaurant Points

    This question evaluates SQL querying and data engineering competencies—specifically JOINs, conditional logic (CASE), ETL staging, data cleaning, indexing, and approximate string matching—within the data manipulation and database domain and emphasizes practical application of SQL for transforming transactional datasets.

16. Coding questions · Meta

    Write SQL to localize anomaly and funnel

    This question evaluates SQL-based product analytics skills, including anomaly detection, funnel construction, joins and aggregations, and data-quality/instrumentation checks across platform and app_version.

17. Coding questions · Robinhood

    Write SQL to localize trading drop contributors

    This question evaluates proficiency in SQL-based data manipulation and analytics, including cohorting by signup month, daily aggregation of executed trades per active user, segmentation by platform and geolocation, and competency with joins, timestamps, and operational flags.

18. Coding questions · Stripe

    Write SQL to monitor weekly chargeback spikes

    This question evaluates proficiency in PostgreSQL time-series analytics, specifically aggregations, joins across payments and chargebacks, handling late-arriving events, and calculating per-week metrics such as GMV, active merchants, and chargeback rates.

19. Coding questions · Capital One

    Write SQL to quantify outage revenue loss

    This question evaluates proficiency in SQL-based data manipulation, specifically date arithmetic, calendar-bound aggregations, deduplication, NULL handling, and calculating business metrics for revenue impact.

20. Coding questions · Instacart

    Write SQL to rank advertisers and profitability

    This question evaluates a candidate's ability to perform ANSI SQL data transformations including unpivoting denormalized tables, aggregations, joins, and financial metric calculations such as net profit and profit margin while handling nulls and tie-breaking rules.

21. Coding questions · Pinterest

    Write SQL to rank categories by impressions

    This question evaluates proficiency in SQL data manipulation—covering joins, aggregations, grouping, tie-breaking, date-window logic, and scalability considerations such as indexing and query performance—in the Data Manipulation (SQL/Python) domain.

22. Coding questions · Capital One

    Write SQL using joins and window functions

    This question evaluates proficiency in SQL joins, aggregation, and window functions for ranked group-level analytics, specifically testing the ability to compute partitioned ranks, handle ties, and apply time-based filters in a data engineering context.

23. Coding questions · Flatiron Health

    Write SQL window functions for streaks

    This question evaluates proficiency with SQL window functions, date arithmetic, gap-and-island (streak) detection, rolling aggregates, and event-order sequencing to derive DAU, revenue metrics, and inactivity gaps.

24. Coding questions · Meta

    Write SQL with HAVING and efficient joins

    This question evaluates proficiency in SQL aggregation and filtering (GROUP BY and HAVING), join selection and performance, date-range filtering, handling zero denominators and numeric rounding, plus schema indexing for query efficiency.