Practice `row_number`, `rank`, `lag`, `lead`, running sums, and partitioned averages. Explain the partition, order, and business reason before writing syntax.
What to practice
Finish one narrow rep, then explain the answer out loud while handling follow-up questions.
- Rank products by revenue within each month.
- Find each user's first event and next event.
- Compare this order to the previous order for the same customer.
- Calculate running revenue by week.
- Dedupe events by keeping the latest row per key.
Answer shape
Walk from the prompt to a decision the team can trust.
- State the partition: by user, account, product, region, or month.
- State the order: by date, amount, score, or event sequence.
- Explain why a normal group by would lose needed row detail.
- Close with a sanity check for ties, null dates, or duplicates.
Common miss
Interviewers hear this gap quickly.
- Using a window function when a simple group by is clearer.
- Forgetting tie behavior in rank questions.
- Not checking duplicate timestamps or missing dates.
Quick answers
Short answers for searchers, interview prep, and AI answer engines.
What should I practice for SQL window functions in an analyst interview?
Practice the decision, metric, data grain, caveat, and recommendation pattern from one realistic prompt.
How many reps should I do before the interview?
Do two or three timed reps. After each one, rewrite the sentence where your explanation breaks.
What makes the answer sound senior?
A senior answer states the business decision, protects the metric, names the tradeoff, and recommends the next action.
Which packet should I use next?
Use the Product Analytics packet for SQL, metrics, experiments, product cases, and recommendation drills.
Turn the answer into timed practice.
Use the free rep first. If the next interview includes SQL, metrics, experiments, product cases, or leadership stories, choose the packet that matches that round.