MockSQL3 Submitted

[PranathiDeepak]

No description provided.

[super30admin]

The student's solution demonstrates a good understanding of SQL concepts and problem-solving approaches. Here's a detailed evaluation:

1. Problem1.sql:

   • Correctness: The solution correctly identifies the second item sold by each seller and checks if it matches their favorite brand. The use of DENSE_RANK() is appropriate here.
   • Time Complexity: O(n log n) due to the window function and joins.
   • Space Complexity: O(n) for storing intermediate results in CTEs.
   • Code Quality: Well-structured with clear CTEs. The column alias '2nd_item_fav_brand' should use standard naming conventions (e.g., "second_item_fav_brand").
   • Edge Cases: Handles cases where a seller hasn't sold any items or only one item (LEFT JOIN ensures all users are included).

2. Problem2.sql:

   • Correctness: Correctly calculates total scores for each player and identifies the top player in each group. The UNION ALL approach for combining scores is appropriate.
   • Time Complexity: O(n log n) due to window functions and sorting.
   • Space Complexity: O(n) for storing intermediate results.
   • Code Quality: Good use of CTEs but could be improved with more descriptive names (e.g., "player_scores" instead of "CTE"). The final query could be simplified by directly filtering in CTE3.
   • Edge Cases: Handles ties correctly by ordering by player_id when scores are equal.

General Improvements:

• Use more descriptive CTE names for better readability.
• Consider adding comments for complex logic.
• Standardize naming conventions (avoid quotes around column aliases unless necessary).
• For Problem2.sql, the final ORDER BY in CTE3 is unnecessary since you're reordering in the outer query.