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Top 50 null handling Interview Questions

The most frequently asked null handling questions across all roles and companies, ranked by real interview frequency. Updated daily.

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51companies covered
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1
null handlingStart here. 26 questions · ~520 min
Write a SQL QueryMedium
Practice
Recently asked

Summarize annual user engagement with a left join, aggregation, and NULL-safe duration handling.

null handlingJoinssql queryNBCUniversalCCourseraMeta Platforms
SQL for Channel MetricsMedium
Practice

Combine campaign, performance, and conversion data to calculate channel-level marketing metrics.

null handlingJoinsGroup ByHorizon MediaPATH
Clean Null Campaign MetricsEasy
Practice

Use CASE and COALESCE to standardize missing StackAdapt campaign metrics and count incomplete rows by campaign.

null handlingData WranglingReconciliationStackadaptCvent
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2
Window Functions6 questions · ~120 min
Rolling 7-Day Prescriptions AverageMedium
Practice
Recently asked

Calculate rolling seven-day prescription averages by region from daily prescription totals.

Window FunctionsDate Functionsnull handlingBBeviGSK
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3
Date Functions3 questions · ~60 min
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4
missing values4 questions · ~80 min
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5
Subqueries5 questions · ~100 min
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6
More topics6 questions · ~120 min
SQL JOIN With Missing ValuesMedium
Practice

Use a JOIN and COALESCE to return related rows while replacing missing values with defaults.

postgresqlnull handlingJoinsAmazonAmazon Web Services
Nth Salary SQLMedium
Practice
Recently asked

Use ranking to return the nth distinct salary from an employee table.

system designnull handlingsqlBBirdeyeAkamai
Mutual Follows QueryMedium
Practice
Recently asked

Use a self-join to return each mutual follower pair once, with the lower user ID first.

data relationshipsnull handlingJoinsBee RoboticsSupermicro
SQL Data Quality ChecksHard
Practice

Detect missing fields, duplicate transaction keys, invalid amounts, and merchant reference issues with PostgreSQL CTEs and joins.

Data Qualitynull handlingdata integritySigmoidCox Automotive
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