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

SQL Approach to Cleaning Campaign Data

EasySQL & Data Manipulation00:00
Practice interviewer
In session
5 left
00:00

Your question is SQL Approach to Cleaning Campaign Data. Take a moment with it on the right.

Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).

You need to log in / sign up to chat or submit.

Problem

Context

Clean input data is critical before you analyze BMW Group campaign performance in tools such as BMW Group Adobe Analytics dashboards or CRM reporting. Interviewers usually want to hear how you make raw data reliable before any KPI or audience analysis.

Question

Explain how you approach data cleaning and preparation in SQL. Walk through how you would inspect a raw marketing table, identify bad or inconsistent values, handle NULLs, standardize text fields, remove duplicates, and prepare a trusted dataset for downstream reporting.

Scope guidance

Keep your answer practical and SQL-focused. You should describe the sequence of checks you would run, the PostgreSQL techniques you would use, and how you would balance correctness, reproducibility, and auditability rather than giving only high-level data quality principles.