Top 50 data anomaly Interview Questions
The most frequently asked data anomaly questions across all roles and companies, ranked by real interview frequency. Updated daily.
Use window functions and conditional aggregation to flag completed transactions that may duplicate one another within five minutes.
Revolut
RobinhoodIdentify multi-day streaks of anomalous email sending activity for a specific user using PostgreSQL window functions.
TessianIdentify transactions with missing fields or store-level amount outliers using PostgreSQL data-quality logic.
Walmart de México y CentroaméricaClassify missing and statistically unusual financial transactions using PostgreSQL aggregates, joins, and CASE logic.
BlackRock
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Calculate each sale's z score against the non-null sales distribution using PostgreSQL.
AmazonIdentify every row whose three-column combination occurs more than once, including the original row identifier.
JefferiesUse a CTE to find repeated manufacturing telemetry signatures and return their counts and record identifiers.
Jabil
ASMLIdentify metric segments with significant declines by comparing recent and prior period averages.
Autodesk
Robert Half