SQL5 Done

[Aniruddh-2512]

sql 5 done

[super30admin]

Let me evaluate each of the SQL files separately:

1. averagesalary.sql:

   • Correctness: The solution appears to correctly calculate department vs company salary averages and compare them. The use of window functions is appropriate.
   • Time Complexity: O(n) for the window functions, which is efficient.
   • Space Complexity: Creates temporary tables S and T, but this is reasonable for the problem.
   • Code Quality: Well-structured with clear CTEs. The CASE statement is readable.
   • Improvement: Could add comments explaining the logic, especially the window function partitioning.

2. gameplayanalysis1.sql:

   • Correctness: Correctly finds the first login date for each player.
   • Time Complexity: O(n) for the GROUP BY and MIN operations.
   • Space Complexity: Minimal, just grouping and aggregating.
   • Code Quality: Simple and concise. No improvements needed for this straightforward query.

3. reportcontiguous.sql:

   • Correctness: The solution correctly identifies contiguous periods of success/failure. The use of RANK() with SUBDATE is clever.
   • Time Complexity: O(n log n) due to the window function and sorting.
   • Space Complexity: Creates temporary tables, but necessary for the problem.
   • Code Quality: Well-structured with clear CTEs. The logic is complex but well-organized.
   • Improvement: Could add comments explaining the SUBDATE trick for identifying contiguous dates.

4. studentreports.sql:

   • Correctness: Correctly pivots student data by continent. The ROW_NUMBER() and MAX(IF()) approach is standard for this type of pivot.
   • Time Complexity: O(n log n) for the window function and grouping.
   • Space Complexity: Creates a temporary table, but reasonable.
   • Code Quality: Clear and concise. The pivot logic is well-implemented.
   • Improvement: Could use a more descriptive name than 'T' for the CTE.

General strengths:

• Consistent use of CTEs for better readability
• Appropriate use of window functions
• Good SQL formatting and indentation

Areas for improvement:

• Could add more comments explaining complex logic
• Some CTE names could be more descriptive
• Consider adding error handling for edge cases (like empty tables)