Completed Sql2

[DhruvParashar246]

No description provided.

[super30admin]

1. Department Top 3 Salaries.sql:

   • Correctness: The solution correctly identifies the top 3 salaries per department using DENSE_RANK(), which handles ties appropriately.
   • Time Complexity: O(n log n) due to the sorting required for the window function.
   • Space Complexity: O(n) for storing the CTE results.
   • Code Quality: Well-structured with clear column aliases. Consider adding a WHERE clause to filter out NULL department names if needed.
   • Efficiency: Good use of DENSE_RANK() which is optimal for this problem.

2. Exchange Seats.sql:

   • Correctness: Correctly handles seat swapping for odd/even IDs and the edge case of the last odd ID.
   • Time Complexity: O(n) for the COUNT operation and O(n log n) for the final sorting.
   • Space Complexity: O(1) additional space beyond input.
   • Code Quality: The CASE statement is clear. Consider using a CTE for the count to improve readability.
   • Efficiency: Efficient approach overall. The cross join with Seat_Counts is slightly unconventional but works.

3. Rank Scores.sql:

   • Correctness: Correctly ranks scores with DENSE_RANK() to handle ties.
   • Time Complexity: O(n log n) for the sorting in the window function.
   • Space Complexity: O(n) for the result set.
   • Code Quality: Simple and effective. No improvements needed.
   • Efficiency: Optimal solution for this problem.

4. Tree Node.sql:

   • Correctness: Correctly identifies root, inner, and leaf nodes through UNION operations.
   • Time Complexity: O(n^2) due to the NOT IN subquery which performs a full scan for each row.
   • Space Complexity: O(n) for the result set.
   • Code Quality: Clear logic but could be optimized. The repeated subquery could be moved to a CTE.
   • Efficiency: Could be improved by using JOINs instead of NOT IN for better performance.

General strengths:

• Consistent use of appropriate SQL functions for each problem
• Clear and readable formatting
• Correct handling of edge cases in most solutions

Areas for improvement:

• Consider using JOINs instead of NOT IN for better performance in Tree Node.sql
• Could add comments to explain complex logic
• Some queries could benefit from CTEs for better readability