Completed MockSQL

[kaaviyavarrshini]

No description provided.

[super30admin]

1. Correctness:

• Problem1_TopTravellers.sql: The solution correctly uses a window function with COALESCE to handle NULL values, which is appropriate for calculating total distances traveled. The LEFT JOIN ensures all users are included, even those without rides.
• Problem2_ApplesOranges.sql: The solution correctly calculates the difference between apples and oranges sold per day using a CTE and conditional aggregation. This approach effectively handles the pivoting of fruit types.

2. Time Complexity:

• Both solutions appear to have reasonable time complexity for typical database operations (O(n) for scans with proper indexing). The window function in Problem1 might add some overhead but is generally efficient.

3. Space Complexity:

• The space usage is appropriate for both solutions. The CTE in Problem2 creates temporary storage but is necessary for the calculation.

4. Code Quality:

• Both solutions are well-structured and readable.
• Good use of COALESCE in Problem1 to handle NULL values.
• Problem2 effectively uses a CTE for clarity.
• Consistent formatting and indentation.
• Could benefit from brief comments explaining the logic, especially for less experienced readers.

5. Efficiency:

• Problem1 could potentially be rewritten with a GROUP BY instead of a window function, which might be more efficient in some database systems.
• Problem2's approach is already quite efficient, though some might prefer using PIVOT if the database supports it.

Areas for Improvement:

• Consider adding comments to explain the purpose of each query part.
• In Problem1, while the window function works, a GROUP BY approach might be more conventional for aggregation.
• The column alias in Problem2's CTE uses single quotes which is not standard SQL (should use double quotes or backticks depending on the SQL dialect).