CARD91 Interview Questions
The questions to prepare for CARD91 interviews, across all roles. Questions from real interview reports rank first. Updated weekly.
Explain how INNER JOIN and LEFT JOIN differ, and when to use each for matched-only versus all-left-row analysis.
Explain the four ACID properties and why they matter for reliable transaction processing in SQL systems.
Explain the purpose of using indexes in databases and their impact on query performance.
Compute top 10 customers by net sales using joins and aggregations, ordering by revenue with deterministic tie-breaking.
Gain Digital
TCS
Zest AIUse joins and LAG to isolate departments driving a large month-over-month spending variance.
State of California
University of Chicago
The Church of Jesus Christ of Latter-day SaintsCombine customer transactions and optional notes using INNER JOIN, LEFT JOIN, aggregation, and conditional spend bands.
Supernova Technology
DeloitteExplain how to derive time and space complexity for a coding solution, including loops, recursion, and auxiliary memory.
Tests your understanding of Java collections tradeoffs and when to choose each in real applications.
Tests your algorithmic thinking and ability to choose efficient sorting strategies.
Tests your ability to implement an efficient cycle detection algorithm.
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Tests your approach to reliability, error handling, and maintainable failure modes.