This is a premium problem. We're working on making it available for free soon.
Explore Free ProblemsSolutions for this premium problem will be available for free soon.
Browse Free ProblemsWatch expert explanations and walkthroughs
Practice problems asked by these companies to ace your technical interviews.
Explore More ProblemsJot down your thoughts, approach, and key learnings
Problems involving ranking, grouping, and tie-breaking with SQL are common in data-focused interviews at major tech companies. This question tests knowledge of window functions, aggregation, and SQL query design, which are frequently evaluated.
The most straightforward approach is using a SQL window function such as ROW_NUMBER() partitioned by student_id and ordered by grade descending and course_id ascending. This ranks courses per student and allows you to select the top-ranked record. It handles both the highest grade and the tie-breaking rule cleanly.
Window functions are particularly useful for this problem. They allow ranking or ordering rows within each student's group without collapsing rows like a GROUP BY would. Functions such as ROW_NUMBER(), RANK(), or DENSE_RANK() are commonly used.
Yes, it can also be solved using aggregation. You can compute the maximum grade per student using GROUP BY, then join back to the original table and select the smallest course_id among the tied records.
