Completed Sql6

[DhruvParashar246]

No description provided.

[super30admin]

1. Combine Two Tables.sql:

   • Correctness: The solution correctly uses a LEFT JOIN to include all persons even if they don't have an address.
   • Time Complexity: O(n) where n is the number of records in Person table (assuming proper indexing on personID).
   • Space Complexity: O(n) for storing the result set.
   • Code Quality: Well-structured and readable. Follows SQL best practices.
   • Efficiency: Good, no improvements needed.

2. Customers with Strictly Increasing Purchases.sql:

   • Correctness: The logic appears correct for finding customers with strictly increasing yearly purchases.
   • Time Complexity: O(n^2) due to the self-join on the CTE.
   • Space Complexity: O(n) for storing the CTE results.
   • Code Quality: Could improve readability by using more descriptive column aliases (e.g., 'yearly_total' instead of 'price').
   • Efficiency: The self-join approach is correct but could be optimized with window functions.

3. Game Play Analysis II.sql:

   • Correctness: Correctly finds the first login device for each player.
   • Time Complexity: O(n^2) due to the correlated subquery.
   • Space Complexity: O(n) for the result set.
   • Code Quality: Simple and effective. Could use a JOIN with a derived table for better readability.
   • Efficiency: Could be optimized with window functions (ROW_NUMBER()).

4. Game Play Analysis III.sql:

   • Correctness: Correctly calculates running total of games played.
   • Time Complexity: O(n log n) for the window function operation.
   • Space Complexity: O(n) for the result set.
   • Code Quality: Excellent use of window functions. Clear and concise.
   • Efficiency: Optimal solution for this problem.

5. Shortest Distance in a Plane.sql:

   • Correctness: Correctly finds the minimum distance between any two distinct points.
   • Time Complexity: O(n^2) due to the self-join.
   • Space Complexity: O(n^2) for the Cartesian product.
   • Code Quality: Good, but could add a comment explaining the distance formula.
   • Efficiency: The self-join is necessary for this problem, but ensure the table isn't too large.

General improvements:

• Consider using more descriptive column aliases in some queries.
• For correlated subqueries (Game Play Analysis II), window functions might be more efficient.
• Add brief comments explaining complex logic where helpful.