Completed Mock-SQL-3

[HaswathaSridharan]

No description provided.

[super30admin]

The student's solution demonstrates a good understanding of SQL concepts, particularly with the use of Common Table Expressions (CTEs) and window functions. Here are some specific observations:

1. Correctness:

   • For Problem 1 (Market Analysis II), the solution correctly identifies the second item sold by each seller and checks if it matches their favorite brand. The LEFT JOIN ensures all users are included.
   • For Problem 2 (Tournament Winners), the solution correctly calculates total scores for each player and ranks them within their group.

2. Time Complexity:

   • Both solutions involve joins and window functions, which typically operate in O(n log n) time due to sorting operations.
   • The GROUP BY in Problem 2 adds another O(n log n) operation.

3. Space Complexity:

   • The CTEs create temporary tables, so space complexity is O(n) for storing intermediate results.

4. Code Quality:

   • The use of CTEs improves readability.
   • Some improvements could be made:
     • In Problem 1, the column alias "2nd_item_fav_brand" should be quoted or renamed to avoid starting with a number.
     • Consistent indentation would improve readability.
     • The subquery in Problem 2 could be formatted more clearly.

5. Efficiency:

   • Both solutions are generally efficient for their problem domains.
   • No major optimizations are immediately apparent, though using more descriptive CTE names could improve maintainability.

Edge Cases:

• Problem 1 handles sellers with fewer than 2 orders correctly via the LEFT JOIN.
• Problem 2 handles ties correctly with the secondary sort on player_id.