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
Analyze Restaurant Performance With SQL
00:00
5 left

Analyze Restaurant Performance With SQL

MediumSQL · PostgreSQL

Problem

Write a SQL query to analyze Kfc France restaurant performance by day, including sales, food cost, labor cost, and waste, and identify the worst-performing locations.

Use the provided Kfc France restaurant, sales, cost, and waste tables. Treat missing cost or waste values as zero for performance calculations.

Output

  1. One row per restaurant and business date with business_date, restaurant_name, sales, food_cost, labor_cost, waste, operating_contribution, previous_day_contribution, performance_rank, and is_worst_performer.
  2. Include restaurants with sales records only, rank locations from lowest to highest operating contribution within each date, include ties, and order by date, rank, and restaurant name.

Schema

restaurants
ColumnTypeDescription
restaurant_idPKINTUnique Kfc France restaurant identifier
restaurant_nameVARCHAR(100)Restaurant location name
cityVARCHAR(80)French city
regionVARCHAR(80)French administrative region
daily_sales
ColumnTypeDescription
sales_idPKINTDaily sales record identifier
restaurant_idINTReferenced restaurant
business_dateDATETrading date
salesNUMERIC(12,2)Total daily sales in euros
daily_costs
ColumnTypeDescription
cost_idPKINTDaily cost record identifier
restaurant_idINTReferenced restaurant
business_dateDATECost date
food_costNUMERIC(12,2)Daily food cost in euros
labor_costNUMERIC(12,2)Daily labor cost in euros
daily_waste
ColumnTypeDescription
waste_idPKINTDaily waste record identifier
restaurant_idINTReferenced restaurant
business_dateDATEWaste date
wasteNUMERIC(12,2)Daily waste value in euros
Tablesrestaurantsdaily_salesdaily_costsdaily_waste
Interviewer

Your question is Analyze Restaurant Performance With SQL. Start with the requirements and the four 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.