Top 50 query optimization Interview Questions
The most frequently asked query optimization questions across all roles and companies, ranked by real interview frequency. Updated daily.
Optimize a PostgreSQL billing query using selective filtering, pre-aggregation, indexes, and regional ranking.
QuantumBlackDDell Tech Laboratories
ConfluentOptimize a PostgreSQL reporting query by reducing scanned rows, preserving unmatched records, and selecting the latest related review efficiently.
Tata Consultancy Services (North America)PPriority Technology Holdings, LLC
ZillowOptimize a PostgreSQL reporting query using selective filtering, aggregation, indexing strategy, and execution-plan reasoning.
CapgeminiDDeltaX
Melaleuca: The WellnessFind the top 3 users by completed transaction volume in the last 30 days using joins and aggregation.
ChimeOptimize a PostgreSQL aggregation query by filtering early, reducing rows before joins, and returning qualifying active customers.
SofteamSSoftware Medical Informatics
GlassdoorExplain how to reduce latency for a query under heavy multi-tenant load.
SWIFT
FilevineWrite and optimize a PostgreSQL query that summarizes current enrollment activity across studies and sites.
XPO
MedpaceOptimize a PostgreSQL query over millions of event rows using selective predicates, indexing, joins, and latest-row selection.
Okta
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