Dataford
Interview QuestionsInterview GuidesExperiencesCoaching
New
Pricing
Get started
Dataford
Popular roles
Software EngineerData AnalystData ScientistData EngineerBusiness AnalystAI EngineerMachine Learning EngineerProduct Manager
Browse
Browse All RolesEvery role hub, from analyst to MLBrowse All CompaniesCompany-specific interview loopsAll Interview GuidesThe full guide library
Top questions by role
Software EngineerData AnalystData ScientistData EngineerBusiness AnalystAI EngineerMachine Learning EngineerProduct Manager
Top questions by skill
SQLPythonStatisticsMachine LearningA/B TestingSystem DesignGenerative AIProduct SenseMetricsBehavioral
Browse all questions →Try a mock interview
Experiences
Practice
Mock InterviewsTimed interview simulations with feedbackCoaching1:1 coaching with people at your target companiesSuccess PathYour 6-week structured planModulesCurated lessons by topicWebinarsTalks from ex-Big Tech data leadsPlaygroundA free-form scratch editor
Learn
BlogInterview strategy and career adviceTech Job Market ReportHiring trends across data and AI rolesFor UniversitiesDataford for career centersAbout DatafordWho we are and how we build
Pricing
Build my plan
Top Delivery Hubs with Window Functions
00:00
5 left

Top Delivery Hubs with Window Functions

HardSQL · PostgreSQL

Problem

Write a SQL query using window functions to identify the top-performing delivery hubs based on order volume and delivery time for Licious last-mile operations.

Use completed orders from January 2025. Calculate each hub's order volume and average delivery time, rank hubs using the sum of their volume rank and delivery-time rank, and return the three highest-performing hubs.

Output

  1. One row per selected hub with hub_code, hub_name, order_volume, avg_delivery_minutes, volume_rank, delivery_time_rank, performance_score, and performance_rank.
  2. Sort by performance_rank, then hub_code.

Schema

delivery_hubs
ColumnTypeDescription
hub_idPKINTUnique delivery hub identifier
hub_codeVARCHAR(20)Short operational code for the hub
hub_nameVARCHAR(100)Delivery hub name
orders
ColumnTypeDescription
order_idPKINTUnique order identifier
hub_idINTHub assigned to the order
order_statusVARCHAR(30)Current order delivery status
dispatched_atTIMESTAMPTimestamp when the order left the hub
delivered_atTIMESTAMPTimestamp when the order was delivered
Tablesdelivery_hubsorders
Interviewer

Your question is Top Delivery Hubs with Window Functions. Start with the requirements and the two tables in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

You need to log in / sign up to run or submit.
CodePostgreSQL
Sign up free to run your codeLog inLn 1
Run your query to see results here.