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Slowly Changing Dimension Type 2

A hard SQL mock interview question on DataDriven. Practice with AI-powered feedback, real code execution, and a hire/no-hire decision.

Domain
SQL
Difficulty
hard
Seniority
senior, staff

Interview Prompt

We maintain a slowly changing dimension (Type 2) for customer addresses. Each customer_id can appear multiple times, once per address change. The current record is the one where last_name is NULL. Find each customer's current country and how many times they have moved (total records minus 1). Show customer_id, first_name, current country, and move count.

How This Interview Works

  1. Read the vague prompt (just like a real interview)
  2. Ask clarifying questions to the AI interviewer
  3. Write your sql solution with real code execution
  4. Get instant feedback and a hire/no-hire decision