Done sql4 problems

[hinduja97]

No description provided.

[BharathVuppala96]

Good Work

[super30admin]

1. Problem 1.sql:

   • Correctness: The solution correctly calculates the number of accepted candidates for both Senior and Junior categories while respecting the budget constraint. The use of a CTE with window functions is appropriate.
   • Time Complexity: O(n log n) due to the sorting in the window function.
   • Space Complexity: O(n) for storing the CTE.
   • Code Quality: The code is well-structured and readable. The use of a CTE and window function demonstrates good SQL practices.
   • Efficiency: The solution is efficient, but the subquery in the Junior part could be optimized by storing the Senior sum in a variable.

2. Problem 2.sql:

   • Correctness: The solution correctly calculates the matches played, points, goals for, goals against, and goal difference for each team. The UNION ALL approach to handle both home and away matches is correct.
   • Time Complexity: O(n) for the UNION ALL and O(n log n) for the GROUP BY.
   • Space Complexity: O(n) for storing the CTE.
   • Code Quality: The code is well-structured. The CASE statement for points calculation is clear. However, the points are being summed as strings ('3' and '1'), which should be integers for better practice.
   • Efficiency: The solution is efficient, but converting points to integers would be better.

3. Problem 3.sql:

   • Correctness: The solution correctly identifies salespersons who did not have any orders with the company 'Red'.
   • Time Complexity: O(n) for the subquery and O(n) for the main query.
   • Space Complexity: O(n) for the subquery result.
   • Code Quality: The code is simple and effective. The use of NOT IN with a subquery is appropriate here.
   • Efficiency: The solution is efficient for this problem size.

4. Problem 4.sql:

   • Correctness: The solution correctly identifies the person with the most friends by counting both requester and accepter IDs.
   • Time Complexity: O(n) for the UNION ALL and O(n log n) for the GROUP BY.
   • Space Complexity: O(n) for storing the CTE.
   • Code Quality: The code is well-structured and readable. The use of CTEs makes the logic clear.
   • Efficiency: The solution is efficient, but the final WHERE clause could be optimized by using LIMIT 1 if only one result is needed.

General Observations:

• The student demonstrates a good understanding of SQL concepts and uses appropriate techniques for each problem.
• The code is generally clean and follows best practices.
• Minor improvements could be made in type consistency (e.g., using integers instead of strings for points) and potential optimizations in subqueries.