Welcome to your interview.
The question is on your right: Joining Large Datasets in SQL. Take a moment with it first.
Talk your thinking through with me if you like - when you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes). Discussion and graded submissions share your five interviewer interactions, so spend them well.
What is your experience with SQL, and how do you write queries to join multiple large datasets?