Programming Interview Program to Window Function Practice #21 with Explanation
Programming Interview
Hard
DBMS
23 views
1 min read
91 words
This problem helps you practice core Programming Interview fundamentals in a practical way. It builds intuition around score, table, sql. Let’s break it down step by step so you can implement it confidently.
Problem Statement
Table: Scores(user_id, score, created_at). Return each row with the rank of score within the same day.
Input Format
SQL tables are described in the question.
Output Format
Write the SQL query.
Code Solution
This explanation is written for learning purposes and to help beginners understand the concept clearly.
SELECT user_id, score, created_at,
DENSE_RANK() OVER(PARTITION BY CAST(created_at AS DATE) ORDER BY score DESC) AS rnk
FROM Scores;
Output Example
No sample I/O is provided for this question.
Common Mistakes
- Misreading input/output format.
- Not handling constraints and edge cases.
- Off-by-one errors in loops.
- Forgetting to reset variables between test cases (if any).
Solution Guide
Problem
Table: Scores(user_id, score, created_at). Return each row with the rank of score within the same day.
Input / Output
Input
SQL tables are described in the question.
Output
Write the SQL query.
Details
Common Mistakes
- Misreading input/output format.
- Not handling constraints and edge cases.
- Off-by-one errors in loops.
- Forgetting to reset variables between test cases (if any).
Difficulty
Hard
Programming Interview
Official Solution
SELECT user_id, score, created_at,
DENSE_RANK() OVER(PARTITION BY CAST(created_at AS DATE) ORDER BY score DESC) AS rnk
FROM Scores;
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