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Updated weekly · Last refresh Oct 17
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OneAdvanced Software Engineer Interview Questions

The questions to prepare for a OneAdvanced Software Engineer interview. Questions from real interview reports rank first. Updated daily.

3questions
~1htotal time
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1
Technical FundamentalsStart here. 1 question · ~8 min
Four Pillars of OOPEasy

Explain encapsulation, abstraction, inheritance, and polymorphism, including how each works and how they differ in real code.

Language Featuresobject-oriented programmingtechnical fundamentalsOOneAdvanced
2
SQL & Data Manipulation1 question + 3 drills · ~38 min
Understanding Common Table Expressions (CTEs)Medium

Explain what CTEs are and their advantages in SQL queries.

CTEsOOneAdvanced
Write SQL for a Specific ProblemMedium
Practice
Practice drill

Calculate each customer's completed 2025 order totals and classify customers by total value.

JoinsCTEsProblem SolvingEPAM Systems
Handling Missing DataMedium
Practice
Practice drill

Standardize missing observation fields with fallback values, missingness flags, and ordered output.

Window Functionsmissing valuesdata cleaningEversource EnergyCincinnati Children's HospitalAdtalem Global Education
Optimize a Slow SQL QueryHard
Practice
Practice drill

Rewrite a slow PostgreSQL loan payment query to reduce scanned rows while preserving the required aggregated results.

database optimizationJoinsData WranglingAmeripriseEEltro Cyberchrome PrivateEnergyHub

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3
Behavioral & Leadership1 question · ~8 min
Owning a Production Debugging IncidentMedium

Tests ownership during a production incident, including structured debugging, stakeholder communication, and learning from high-pressure technical problems.

experienceProblem SolvingDebuggingOOneAdvanced
The finish line: interview-readyComplete all 3 questions plus 3 hands-on drills to finish this plan.