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
Monthly Sales Aggregation by Product Category
00:00
5 left

Monthly Sales Aggregation by Product Category

EasySQL · PostgreSQL

Problem

Scenario

A retail analytics team wants to analyze monthly sales performance by product category. You are given two tables: sales records individual sales transactions, and products contains product details.

Task

Write a SQL query to calculate the total sales amount for each product category and month.

Requirements

  1. Join sales and products to associate each sale with its category.
  2. Group results by product category and month (in YYYY-MM format).
  3. Calculate the total sales amount per group.
  4. Return only groups where the total sales amount is greater than zero.
  5. Order the output by month ascending, then by category ascending.

Schema

sales
ColumnTypeDescription
idPKINTPrimary key for sales records
product_idINTForeign key referencing products
sale_dateDATEDate of the sale
amountDECIMAL(10,2)Sale amount
products
ColumnTypeDescription
idPKINTPrimary key for product records
nameVARCHAR(255)Name of the product
categoryVARCHAR(255)Category of the product
Tablessalesproducts
Interviewer

Your question is Monthly Sales Aggregation by Product Category. 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.