Completed Sql4

[Paneripatel]

No description provided.

[super30admin]

1. Correctness:

   • FriendRequestsII.sql: The solution correctly identifies the person with the most friends by combining requester and accepter IDs and counting occurrences. This approach is correct.
   • LeagueStatistics.sql: The solution correctly calculates the league statistics by considering both home and away matches and applying the correct point system. The ordering is also correctly implemented.
   • SalesPerson.sql: The solution correctly identifies salespersons who haven't sold any products to the company 'RED'.
   • TheNumberOfSeniorsAndJuniorsToJoinTheCompany.sql: The solution correctly calculates the number of seniors and juniors that can be hired within the budget, considering the cumulative sum of salaries. The logic for handling the remaining budget for juniors is correctly implemented.

2. Time Complexity:

   • FriendRequestsII.sql: O(n log n) due to the GROUP BY and ORDER BY operations.
   • LeagueStatistics.sql: O(n log n) due to the GROUP BY and ORDER BY operations.
   • SalesPerson.sql: O(n) for the subquery and main query.
   • TheNumberOfSeniorsAndJuniorsToJoinTheCompany.sql: O(n log n) due to the window function and subsequent filtering.

3. Space Complexity:

   • All solutions use O(n) space for the CTEs and intermediate results, which is reasonable for these problems.

4. Code Quality:

   • The code is generally well-structured and readable.
   • Consistent use of CTEs for complex queries improves readability.
   • Proper indentation and formatting are maintained.
   • The use of descriptive column aliases enhances understanding.

5. Efficiency:

   • The solutions are efficient for the given problems. However, for very large datasets, indexing on the columns used in JOINs and WHERE clauses could improve performance.
   • In TheNumberOfSeniorsAndJuniorsToJoinTheCompany.sql, the use of IFNULL to handle cases where no seniors are hired is a good practice.

Areas for Improvement:

• Adding comments to explain complex logic, especially in TheNumberOfSeniorsAndJuniorsToJoinTheCompany.sql, would enhance readability.
• Consider using more descriptive names for CTEs (e.g., 'FriendCounts' instead of 'CTE' in FriendRequestsII.sql).
• In LeagueStatistics.sql, the column aliases could be more descriptive (e.g., 'home_team' instead of 'r1').

[super30admin]

Let me evaluate each solution one by one:

1. FriendRequestsII.sql:

   • Correctness: The solution correctly identifies the person with the most friends by combining requester and accepter IDs and counting occurrences.
   • Time Complexity: O(n) for the UNION ALL and O(n log n) for the GROUP BY, making it O(n log n) overall.
   • Space Complexity: O(n) for the CTE storage.
   • Code Quality: Well-structured and readable. Good use of CTE.
   • Efficiency: Could potentially optimize by using a more efficient counting method, but current approach is reasonable.

2. LeagueStatistics.sql:

   • Correctness: Correctly calculates league statistics by considering both home and away matches.
   • Time Complexity: O(n) for the UNION ALL and O(n log n) for the GROUP BY, making it O(n log n) overall.
   • Space Complexity: O(n) for the CTE storage.
   • Code Quality: Well-structured with clear CASE statements. Good use of CTE.
   • Efficiency: The approach is efficient for the problem requirements.

3. SalesPerson.sql:

   • Correctness: Correctly finds salespersons who didn't have orders with 'RED' company.
   • Time Complexity: O(n) for the subquery and O(n) for the main query, making it O(n) overall.
   • Space Complexity: O(n) for the subquery result storage.
   • Code Quality: Simple and effective solution. Good use of NOT IN.
   • Efficiency: Could potentially use NOT EXISTS instead of NOT IN for better performance with large datasets.

4. TheNumberOfSeniorsAndJuniorsToJoinTheCompany.sql:

   • Correctness: Correctly calculates the number of seniors and juniors that can be hired within budget.
   • Time Complexity: O(n log n) for the window function and O(n) for the counting, making it O(n log n) overall.
   • Space Complexity: O(n) for the CTE storage.
   • Code Quality: Well-structured with clear logic. Good use of window functions.
   • Efficiency: The solution is efficient and handles the budget constraint well.

General strengths:

• Consistent use of CTEs where appropriate
• Clear and readable SQL formatting
• Good handling of problem requirements
• Appropriate use of SQL features like window functions, CASE statements, etc.

Areas for improvement:

• Could add comments explaining complex logic
• For SalesPerson.sql, consider using NOT EXISTS instead of NOT IN
• Could potentially optimize some queries with indexes if this were production code