Highest Grade For Each Student — LeetCode 1112 Python Solution

Table: Enrollments +---------------+---------+ | Column Name | Type | +---------------+---------+ | student_id | int | | course_id | int | | grade | int | +---------------+---------+ (student_id, course_id) is the primary key (combination of columns with unique values) of this table. grade is never NULL.

+---------------+---------+
| Column Name   | Type    |
+---------------+---------+
| student_id    | int     |
| course_id     | int     |
| grade         | int     |
+---------------+---------+
(student_id, course_id) is the primary key (combination of columns with unique values) of this table.
grade is never NULL.

import duckdb
import pandas as pd

def solution(enrollments: pd.DataFrame) -> pd.DataFrame:
    con = duckdb.connect()
    con.register("Enrollments", enrollments)
    return con.execute("""WITH
    T AS (
        SELECT
            *,
            RANK() OVER (
                PARTITION BY student_id
                ORDER BY grade DESC, course_id
            ) AS rk
        FROM Enrollments
    )
SELECT student_id, course_id, grade
FROM T
WHERE rk = 1
ORDER BY student_id;""").df()