Completed Sql1

[Sairohith070]

No description provided.

[super30admin]

The student has not provided any solution to the problem. Without any code or approach to evaluate, it's impossible to assess correctness, time complexity, space complexity, code quality, or efficiency.

To improve, the student should:

1. Attempt to solve the problem first before submitting
2. Provide at least a basic approach or pseudocode if they're stuck
3. Clearly state any difficulties they're facing if they can't complete the solution

Since this is a medium difficulty SQL problem, the student should demonstrate understanding of basic SQL concepts like SELECT queries, JOIN operations, WHERE clauses, and potentially aggregate functions depending on the specific problem requirements.

[Sairohith070]

I’ve solved the problems and confirmed that the solutions are working correctly on my end. I've also submitted everything as required. Could you please let me know if there’s anything wrong or if something didn’t come through properly on your side?

[super30admin]

1. Problem1.sql:

   • Correctness: The query correctly filters countries with area >= 3,000,000 or population >= 25,000,000, which appears to solve the problem.
   • Time Complexity: O(n) where n is the number of rows in the world table, as it requires a full table scan.
   • Space Complexity: O(1) as it only returns the filtered rows without additional storage.
   • Code Quality: Simple and readable, follows standard SQL syntax.
   • Efficiency: No obvious optimizations needed for this straightforward query.

2. Problem2.sql:

   • Correctness: The function correctly implements the Nth highest salary using DENSE_RANK(), which handles ties appropriately.
   • Time Complexity: O(n log n) due to the sorting operation for DENSE_RANK().
   • Space Complexity: O(n) for storing the temporary ranked results.
   • Code Quality: Well-structured with proper indentation. The use of DENSE_RANK() is appropriate for this problem.
   • Efficiency: The solution is optimal for this type of problem. No improvements needed.

3. Problem3.sql:

   • Correctness: The query correctly deletes duplicate emails, keeping only the record with the smallest id.
   • Time Complexity: O(n^2) in worst case due to the self-join operation.
   • Space Complexity: O(n) for storing the temporary join results.
   • Code Quality: The query is concise but could benefit from a comment explaining the logic.
   • Efficiency: While functional, this could be optimized using a subquery with MIN(id) and NOT IN for better performance on large datasets.

General Observations:

• The solutions demonstrate good understanding of SQL concepts.
• File naming consistency could be improved (Problem1.sql vs problem2.sql).
• Problem3.sql could benefit from a comment explaining the deletion logic.
• All solutions follow standard SQL syntax and are generally well-written.