Start by clarifying the table schema and the definition of 'past 30 days' (e.g., relative to current date or a specific date). Then write a SQL query that filters posts within the last 30 days, groups by user, counts posts, and orders by count descending. Consider edge cases like users with zero posts and whether to include them.
Pro tip: Mention that in a real-world scenario, you might need to handle time zones and ensure the date filter is efficient by using an index on the creation timestamp. Also, consider if the metric should include all users or only active users, as this impacts the query and business interpretation.
Ask about the exact table name, column names, and whether 'past 30 days' is relative to today or a specific date. Confirm if users with zero posts should be included.
Use a WHERE clause with a date function (e.g., creation_timestamp >= CURRENT_DATE - INTERVAL '30 days') to select only recent posts.
Use GROUP BY user_id and COUNT(*) to get the number of posts per user. If including users with zero posts, use a LEFT JOIN from a users table.
Order the results by post count descending. Optionally, include the user_id and post_count in the SELECT clause.
Check for NULLs, time zone considerations, and performance implications. Discuss how the query would scale and any assumptions made.
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