aggregation Interview Questions
28 interview questions in our bank cover aggregation, most of them Coding & Leetcode-style Questions. They average 3.0/5 difficulty — medium — and each one was reported by a candidate after a real interview. Companies known to ask about aggregation: Notion, Zoox, Discord, Amazon, Stripe, and 13 more.
Practice these on the problems board →Companies that ask about aggregation
Question mix
- Coding & Leetcode-style Questions14
- ML Fundamentals & Algorithms9
- System Design for ML5
Difficulty
- 2/5 — easy5
- 3/5 — medium18
- 4/5 — hard4
- 5/5 — very hard1
Questions tagged aggregation
Top 3 Vendors by Total Charged Dollars in Last 2 Years
3/5This Zoox data engineering assessment tests your ability to write complex analytical database queries involving financial logs and vendor dimensions. You will filter historical purchase records over a specific timeframe, appropriately handle refund relationships, and aggregate monetary values to isolate top performers. It evaluates proficiency in relational database operations, filtering logic, and data grouping. Discover the full evaluation criteria and complete query implementation with a subscription.
ML Fundamentals & AlgorithmsZooxStreaming Social-Media Mentions and Aggregation
5/5This reported Bloomberg machine learning system design interview challenges candidates to construct a robust backend capable of processing a continuous feed of digital news and updates. The architecture must successfully extract entity identifiers, manage flexible aggregations across various temporal boundaries, deliver timely user alerts, and enable rapid textual retrieval over a massive corpus. Participants are evaluated on their ability to handle high throughput, low-latency analytics, and scalable data ingestion pipelines. Access to the comprehensive problem breakdown and expert architectural blueprint requires a paid subscription.
System Design for MLBloombergCountry with the Most Events
3/5This Notion interview question tests your ability to write efficient data aggregation queries over large relational datasets. You will need to calculate activity metrics per geographic region and extract the top-performing territory while handling potential ties correctly. The scenario evaluates how well you structure relational operations to scale smoothly under heavy data volumes. Access to the full problem description and complete model solution requires a subscription.
ML Fundamentals & AlgorithmsNotionTop 3 Vendors by Total Charged Amount in the Last 2 Years (Net of Refunds)
3/5This data aggregation and analytics challenge, reported from interviews at Zoox, evaluates your ability to write complex relational database queries involving financial records and vendor metadata. You are tasked with calculating net financial activity over a multi-year window by properly accounting for purchases and their corresponding refunds, then ranking the top performers accordingly. The exercise tests your mastery of SQL joins, date filtering, conditional aggregation, and window functions. Access to the complete prompt, schema details, and optimized query solution requires a subscription.
ML Fundamentals & AlgorithmsZooxBlock Type with the Most Children
3/5This Notion interview question tests your ability to write advanced database queries and aggregate large-scale hierarchical information efficiently. You are tasked with analyzing a massive relational table representing nested elements to determine which classification type possesses the highest cumulative descendant count. The challenge emphasizes query optimization and grouping techniques to handle extensive data volumes smoothly. To view the complete problem statement, optimal SQL approach, and detailed implementation steps, a subscription is required.
ML Fundamentals & AlgorithmsNotionEvent Type with the Most Events
2/5This Notion data-focused interview question asks you to analyze a large-scale activity log to identify the most frequently occurring categorical entries. Using standard database querying techniques, you will need to aggregate records and correctly handle ties when multiple categories share the peak frequency. The challenge assesses your proficiency with grouping operations and performance considerations when operating on massive datasets. Unlock the complete problem description, optimized query strategies, and expert solutions with a subscription.
ML Fundamentals & AlgorithmsNotionSQL Screening (Joins / Aggregation / Window Functions)
3/5This relational database screening evaluation was featured in a Notion engineering interview, focusing on complex querying over multiple business tables. You will tackle practical data retrieval scenarios involving advanced joins, subqueries, and window functions to extract precise metrics. The exercise measures your ability to write performant queries while correctly managing nulls and row aggregation. Get the complete set of prompts and verified SQL solutions by subscribing today.
ML Fundamentals & AlgorithmsNotionAuction Web Service – Lot Winners
3/5Test your relational database querying capabilities with an e-commerce bidding scenario often seen in data-centric roles at Blizzard. This problem evaluates your mastery of SQL aggregation and table joining techniques, requiring you to extract peak financial offers for individual marketplace lots using conditional grouping clauses. Writing optimized queries for relational data manipulation is the core focus here. The full problem and model solution require a subscription.
ML Fundamentals & AlgorithmsBlizzardTop 3 vendors by city and state in the last 2 years
3/5This Zoox SQL query problem requires you to analyze transactional data to identify top-performing vendors. You need to aggregate transaction amounts for each vendor within specific geographical regions (state and city) over the past two years, calculating a net amount that accounts for both purchases and refunds. The final output should list the top three vendors for each unique state-city combination, ranked by their net amount. This question specifically tests your proficiency with SQL window functions for ranking and data aggregation. The full problem statement and a model solution are available with a subscription.
ML Fundamentals & AlgorithmsZooxPercentage of Blocks Never Edited
3/5Reported from a Notion analytics interview, this SQL challenge involves relational tables tracking workspace documentation and user activity logs to calculate the proportion of untouched content. The task tests proficiency in set operations, conditional aggregation, and handling multi-event relationships efficiently. It measures the ability to translate product usage definitions into clean analytical queries. Access to the full schema, test cases, and optimal SQL solution requires a subscription.
ML Fundamentals & AlgorithmsNotionHighest Average Score Per Person
2/5In this Goldman Sachs interview question, you are given a collection of identity and score pairs to determine the highest average performance achieved by any single individual. The challenge requires careful data aggregation, handling potential edge cases, and considering a streaming follow-up where metrics update dynamically. It assesses your data manipulation and algorithmic efficiency. Access to the full problem text, follow-up variations, and model implementation requires a subscription.
Coding & Leetcode-style QuestionsGoldman SachsDesign Coinbase Explore Real-Time Price Dashboard
4/5In this system design challenge featured by Coinbase, you will architect a high-throughput, low-latency live price streaming dashboard capable of handling massive volumes of cryptocurrency assets and concurrent users. This exercise tests your expertise in real-time data pipelines, sliding window aggregations, caching strategies, and maintaining fault tolerance when upstream exchange feeds degrade. Access to the comprehensive architectural blueprint, scaling strategies, and reference solutions requires a paid subscription.
System Design for MLCoinbaseSQL Windowed Aggregation: Past 7/14/30 Days per Day and Country
3/5Mastering advanced relational database querying is a key requirement for data-focused engineering roles, as highlighted in technical rounds at Discord. This analytics task evaluates your proficiency in utilizing windowed aggregation functions to compute rolling metrics over specific past intervals grouped by calendar days and regions. You must carefully handle deduplication logic and construct efficient queries to process multi-day sliding time frames accurately. Unlock the complete problem statement and verified model solution with a subscription.
Coding & Leetcode-style QuestionsDiscordSQL Aggregation: Video Calls per Country per Day
3/5This database interview challenge, frequently reported at Discord, requires candidates to write efficient queries grouping large-scale telecommunication records by geographical region and chronological date. This assessment evaluates relational database manipulation, handling massive datasets, and writing performant aggregations. Access to the complete problem breakdown, optimal SQL queries, and performance tuning strategies requires a paid subscription.
Coding & Leetcode-style QuestionsDiscordLog Aggregation and Group-By
3/5Process, clean, and organize unstructured telemetry streams into structured analytical reports in this classic Amazon interview task. The challenge examines your proficiency in data transformation, grouping algorithms, and custom sorting logic applied to messy input sequences. You will learn how to handle ambiguous requirements and design resilient parsing pipelines for large datasets. Get immediate access to the full problem text and clean implementation details through a subscription.
Coding & Leetcode-style QuestionsAmazonDesign a Metric Counter Library
4/5Design a scalable event tracking and aggregation library in this popular Stripe system design challenge. You will build a system architecture capable of ingesting high-throughput numerical metrics, attaching multi-dimensional metadata tags, and efficiently computing sliding-window aggregates over various time frames. This scenario tests your understanding of concurrency, memory management, and data structures tailored for high-performance analytics workloads. The exhaustive architectural blueprint and reference implementation require a subscription.
System Design for MLStripeClassify User Engagement Patterns from Sessions
2/5In this Netflix interview scenario, you are tasked with analyzing user consumption habits by categorizing viewing sessions into distinct engagement tiers based on completion ratios, then aggregating individual dominant preferences. The challenge evaluates data aggregation, grouping operations, and dictionary mapping skills using viewing logs. Unlock the full description and complete programmatic solution with a subscription.
Coding & Leetcode-style QuestionsNetflixDetect Abusive Books in a Reading Event Stream
3/5Tackle a practical data stream processing challenge frequently reported in Amazon interviews by building a system to flag suspicious listening activity. This problem tests your ability to design efficient tracking mechanisms, manage state across streaming user interactions, and evaluate proportional thresholds for abusive behavior. You will need to consider data structures that handle high-frequency updates while maintaining accurate historical tracking per entity. Unlock the complete problem breakdown, algorithmic strategies, and reference code by purchasing a subscription.
Coding & Leetcode-style QuestionsAmazonStudent Grade Processing (Subject Average, Filter, Top-K, Median)
3/5Mastering data manipulation and aggregation is essential for backend engineering interviews, as highlighted by this Adobe assessment. Candidates are asked to process a collection of academic records to compute subject-wise averages, apply conditional filters, extract leading performers, and determine statistical median values. This task evaluates your ability to handle complex data transformations efficiently using standard programming constructs. Access to the complete problem breakdown, optimal algorithms, and verified code solutions requires a paid subscription.
Coding & Leetcode-style QuestionsAdobeActive Couriers Timeline from Overlapping Intervals
3/5In this Uber interview scenario, you are tasked with analyzing overlapping timeframes for delivery personnel to construct a continuous schedule of active worker counts. The exercise tests your proficiency with interval processing, sorting events, and consolidating overlapping ranges efficiently. Unlock the full challenge details and verified code solution with an active subscription.
Coding & Leetcode-style QuestionsUberFetch Wikipedia via API, then Filter and Aggregate Results
3/5This reported Cresta interview question evaluates your ability to interact with external web services by fetching data from the Wikipedia API and processing the payload. Candidates must correctly handle network headers, parse structured responses, and apply custom filtering and aggregation logic to the retrieved content. This exercise tests practical API integration skills combined with data manipulation techniques in a real-world scenario. Access to the complete problem description and an optimized model solution requires a subscription.
Coding & Leetcode-style QuestionsCrestaChat Session Billing
3/5Handling usage-based pricing models is a practical programming task frequently encountered in software engineering interviews at Stripe. This exercise evaluates your ability to process consumer activity logs, aggregate resource consumption metrics accurately, and compute financial statements based on tiered block pricing rules. It tests core data aggregation, rounding logic, and dictionary manipulation techniques in a realistic billing domain. To view the complete problem statement and review the expert model solution, a paid subscription is required.
Coding & Leetcode-style QuestionsStripeTable Aggregation (Group-By Sum)
2/5Practice a foundational data grouping exercise frequently featured in technical evaluations reported at Notion. Candidates are tasked with processing a collection of key-value pairs to aggregate totals for identical categories efficiently. This scenario examines basic data structuring, stream reading, and accumulator logic in a straightforward format. Accessing the complete problem statement and clean code implementation requires an active subscription.
Coding & Leetcode-style QuestionsNotionOrder Processing System
3/5In this Da Vinci Trading interview scenario, you are tasked with engineering a high-performance order processing system capable of ingesting financial exchange data feeds in real time. The goal is to efficiently maintain and query daily statistics, including total transaction volume, the top three largest purchase orders ranked by monetary value, and the optimal selling price at any given timestamp. Developing this solution requires balancing fast data retrieval with continuous stream updates. Unlock the complete challenge breakdown and expert implementation details with a subscription.
Coding & Leetcode-style QuestionsDa Vinci TradingDesign a Distributed Metrics System
4/5Tackle a distributed telemetry and observability challenge inspired by infrastructure interviews at Snowflake. This scenario assesses your competence in building high-throughput ingestion pipelines that can store massive volumes of time-series records efficiently while supporting low-latency analytical queries and alerting windows. You must consider storage formats, downsampling strategies, and horizontal scalability for heavy read-write workloads. The full problem and model solution require a subscription.
System Design for MLSnowflakeDesign an Ad Click Aggregation Pipeline
4/5This intricate data pipeline design challenge, shared from an Apple engineering interview, centers on processing massive volumes of promotional interaction metrics from diverse traffic channels in near real time. The scenario emphasizes maintaining strict calculation precision for billing and auditing purposes while successfully managing duplicate transmissions, network delays, and heavy burst traffic. Candidates must architect a resilient streaming infrastructure capable of multidimensional slicing and rapid dashboard updates. Gain full access to the complete problem specifications and expert system architecture by subscribing today.
System Design for MLAppleElection Exit Poll by State Report (Top-3 states per candidate with ties)
3/5This Point72 database query challenge requires extracting and ranking electoral poll statistics from relational tables. Candidates must write an advanced SQL script to aggregate votes by territory and identify top-performing candidates across distinct vote volume tiers while correctly handling tied outcomes. This problem evaluates proficiency with window functions, subqueries, and complex data grouping. To view the complete database schema, test queries, and optimal SQL script, a paid subscription is required.
Coding & Leetcode-style QuestionsPoint72Basic SQL Query Aggregation
2/5Database querying and data aggregation are essential competencies for backend developers, as evaluated in foundational SQL assessments like this one from Demonware. This challenge requires you to design a relational table structure and write a database query that groups records to compute statistical metrics, such as category averages. It tests your understanding of relational database design, group-by clauses, and basic aggregate functions. Unlock the full exercise details and verified SQL solution by subscribing today.
Coding & Leetcode-style QuestionsDemonware
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aggregation interview FAQ
- How many aggregation interview questions are there?
- 28 reported questions, mostly Coding & Leetcode-style Questions.
- Which companies ask aggregation questions?
- Notion (6), Zoox (3), Discord (2), Amazon (2), Stripe (2), Bloomberg (1), Blizzard (1), Goldman Sachs (1).
- How hard are aggregation questions?
- They average 3.0 out of 5: 5 at 2/5, 18 at 3/5, 4 at 4/5, 1 at 5/5.