Start by clarifying the schema and definitions (e.g., what 'unconnected' means, how to identify same-day duplicates, and the exact 7-day window). Then build the query in layers: filter views by duration and date, join to a connections table to exclude connected users, and finally count distinct posts. Use DISTINCT on post_id to handle duplicates and ensure each post is counted once.
Pro tip: Explicitly state your assumptions about the data model (e.g., connections are bidirectional, view duration is in seconds) and mention that you would validate the query with edge cases like boundary dates and users with multiple views. This shows you think about data quality and reproducibility.
Ask about the table structures (views, users, connections), definitions of 'unconnected', 'same-day duplicate', and the exact 7-day window (inclusive/exclusive). Confirm that 'lasting more than 60 seconds' means duration > 60.
Select views where duration > 60 and view_date is within the specified 7-day window. Use a subquery or CTE to isolate these views.
Join the filtered views to a connections table (or use NOT EXISTS) to exclude viewers who are connected to the post's author. Ensure the join handles bidirectional connections if needed.
From the resulting set, count distinct post_id to get the number of posts with at least one qualifying view. Use COUNT(DISTINCT post_id) to avoid duplicates from multiple views.
Check for edge cases (e.g., views on the boundary dates, null connections) and consider indexing on date and duration for performance. Explain how you would test the query.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.
First, deduplicate views by keeping the longest duration per post_id, viewer_id, and date, then join reactions on those same keys. Next, aggregate reactions per post per viewer group, and compute the average by dividing total reactions by the distinct count of posts with at least one view in that group, ensuring posts with zero reactions are included.
Pro tip: Explicitly state that you will use a LEFT JOIN from the deduplicated views to reactions and COALESCE zero reactions, because this is a common pitfall that can exclude posts with no reactions and skew the average upward.
For each post_id, viewer_id, and date, keep only the row with the longest duration to resolve same-day duplicate views.
Left join the deduplicated views to the reactions table on post_id, viewer_id, and date, so that views without reactions are retained with zero reactions.
Group by post_id and viewer group (Friend vs. Unconnected), summing reactions per post and counting distinct posts with at least one view.
For each group, divide the total reactions by the distinct count of posts with at least one view, ensuring posts with zero reactions are included in both numerator and denominator.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.