SQL4 problems solved

[Feminto]

No description provided.

[BharathVuppala96]

Good Work

[super30admin]

1. Correctness:

   • friend_requests_II: The solution correctly identifies the person with the most friend requests by combining requester and accepter counts. It handles the problem well.
   • league_stats: The solution accurately calculates team statistics by considering both home and away matches, including points, goals, and goal difference. The ordering is correct.
   • num_of_seniors_juniors: The solution correctly calculates the number of senior and junior candidates that can be hired within the budget, though it could be simplified.
   • sales_person: The solution correctly identifies salespersons who didn't have orders with 'RED' company.

2. Time Complexity:

   • friend_requests_II: O(N) for the initial aggregation and O(N) for the final selection, where N is the number of records.
   • league_stats: O(M) for processing matches (M is number of matches) and O(T) for joining with teams (T is number of teams).
   • num_of_seniors_juniors: O(N log N) due to the sorting in the window function, where N is the number of candidates.
   • sales_person: O(N) for the join and filtering, where N is the number of orders.

3. Space Complexity:

   • All solutions use additional space for CTEs, but this is reasonable for SQL queries. The space complexity is generally O(N) where N is the size of the input data.

4. Code Quality:

   • The code is generally well-structured and readable.
   • Consistent use of CTEs improves readability.
   • Some queries could be simplified (e.g., num_of_seniors_juniors could avoid redundant calculations).
   • Proper indentation and formatting are maintained.

5. Efficiency:

   • friend_requests_II: Efficient, but the subquery could be replaced with a simpler approach using ORDER BY and LIMIT.
   • league_stats: Efficient and well-optimized.
   • num_of_seniors_juniors: The query could be simplified by combining the senior and junior calculations in a single pass.
   • sales_person: Efficient, but using NOT EXISTS might be more readable than NOT IN.