Count Distinct Users — Solution & ExplanationProblems / Count Distinct Users / EditorialApproach

GROUP BY page_url to aggregate per page.

COUNT(DISTINCT user_id) to count unique visitors, not total views.

ORDER BY unique_visitors DESC to rank pages by popularity.

Key ConceptCOUNT(*) counts all rows. COUNT(DISTINCT col) counts only unique values. The difference matters when the same user can appear multiple times (e.g., repeat visits).Hints

COUNT(DISTINCT column) counts only unique values, ignoring duplicates.

In PySpark, use F.countDistinct() instead of F.count().

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