SQL 4 - Submitted

[arushi2106]

SQL Question 1 to 4

[super30admin]

The student's solutions demonstrate a good understanding of SQL concepts and problem-solving skills. Here's a detailed evaluation:

1. Correctness:

• Q1 (SrJr_Union): Correctly handles the senior/junior hiring problem with budget constraints using cumulative sums.
• Q2 (LeagueStats): Properly calculates league statistics by combining home and away matches.
• Q3 (SalesPerson): Correctly identifies salespersons who didn't sell to RED company.
• Q4 (FriendReq): All three approaches correctly find the person with most friend requests, though the window function version is most elegant.

2. Time Complexity:

• All solutions appear to have reasonable time complexity (O(n) or O(n log n) for most operations).
• The Q1 solution could potentially be optimized by combining the senior/junior queries into a single pass.

3. Space Complexity:

• The use of CTEs is appropriate and doesn't create excessive memory usage.
• The multiple approaches for Q4 show good awareness of different implementation strategies.

4. Code Quality:

• Good use of CTEs for readability.
• Consistent formatting and clear column naming.
• The multiple solutions for Q4 demonstrate thoughtful exploration of alternatives.
• Could improve with more comments explaining the logic.

5. Efficiency:

• Q1 could be optimized by calculating both senior and junior counts in one pass.
• Q3 could potentially be written without a CTE using NOT EXISTS.
• The window function version of Q4 is the most efficient approach.

Areas for improvement:

• Adding comments to explain complex logic would enhance maintainability.
• The Q1 solution could be more elegant with a single query instead of UNION.
• Consider using NOT EXISTS in Q3 for potentially better performance.