Dataford
Interview QuestionsInterview GuidesExperiencesMock InterviewsPricing
Get started

Handling Nulls Before Analysis

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

Your question is Handling Nulls Before Analysis. 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

Explain how you would handle missing or NULL values in a PostgreSQL dataset before starting analysis. Focus on a practical workflow: identify missingness, decide whether to keep, filter, or replace NULLs, and explain how simple SQL tools support those choices.

What This Tests

  • Data profiling with basic aggregations
  • Using COALESCE and CASE WHEN appropriately
  • Understanding how NULLs affect counts and averages
  • Making business-aware cleaning decisions