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Aporeon interview preparation

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Querying

Joins, grouping, nulls, pagination, projections, and API-shaped SQL reads.

7 drillsPractice one at a timeOrdered pathConcept question

Recommended start

Inner vs Left Join

Explains join behavior using API-shaped data, missing related rows, and result-cardinality trade-offs.

Easy~5 minStep 1 of 7

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1Inner vs Left JoinRecommended startExplains join behavior using API-shaped data, missing related rows, and result-cardinality trade-offs.Concept questionEasy~5 minSQLSQL ServerPractice 2GROUP BY and HAVING

Practice order

7 drillsOne at a time

1Inner vs Left JoinUp next / Easy / ~5 min
2GROUP BY and HAVINGEasy / ~5 min
3Null SemanticsMedium / ~7 min
4

Explains aggregate queries, grouping keys, filters before and after aggregation, and business-count correctness.

Concept questionEasy~5 minSQLSQL Server

Practice

3Null SemanticsExplains SQL three-valued logic, null-safe filters, optional relationships, and API behavior around missing values.Concept questionMedium~7 minSQLSQL ServerPractice

4Latest Per GroupUses ROW_NUMBER with deterministic partition ordering to return one complete latest row per group, then evaluates index support, tie semantics, scale, and read-model alternatives.Concept questionMedium~7 minSQLSQL ServerPractice

5Keyset PaginationCompares offset and keyset pagination for stable API lists, large tables, and user-facing result consistency.Concept questionMedium~7 minSQLSQL ServerPractice

6Normalization Trade-offsExplains relational modeling, duplication, write consistency, read performance, and when denormalized data is justified.Concept questionMedium~7 minSQLSQL ServerPractice

7API Read ShapeShapes an API list from its contract and cardinality, projecting only required values while preserving authorization, stable pagination, bounded nesting, index support, and measurable query cost.Concept questionMedium~7 minSQLSQL ServerPractice

Latest Per Group

Medium / ~7 min

5Keyset PaginationMedium / ~7 min

6Normalization Trade-offsMedium / ~7 min

7API Read ShapeMedium / ~7 min

Querying - Database SQL | Aporeon