- Difficulty: Hard
- Tags: LeetCode, Hard, Database, leetcode-1412, SQL, O(m + nlogn), O(m + n), 🔒
Problem
Table: Student
+---------------------+---------+ | Column Name | Type | +---------------------+---------+ | student_id | int | | student_name | varchar | +---------------------+---------+ student_id is the primary key (column with unique values) for this table. student_name is the name of the student.
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Table: Exam
+---------------+---------+ | Column Name | Type | +---------------+---------+ | exam_id | int | | student_id | int | | score | int | +---------------+---------+ (exam_id, student_id) is the primary key (combination of columns with unique values) for this table. Each row of this table indicates that the student with student_id had a score points in the exam with id exam_id.
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A quiet student is the one who took at least one exam and did not score the highest or the lowest score.
Write a solution to report the students (student_id, student_name)
being quiet in all exams. Do not return the student who has never taken any exam.
Return the result table ordered by student_id
.
The result format is in the following example.
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Example 1:
Input: Student table: +-------------+---------------+ | student_id | student_name | +-------------+---------------+ | 1 | Daniel | | 2 | Jade | | 3 | Stella | | 4 | Jonathan | | 5 | Will | +-------------+---------------+ Exam table: +------------+--------------+-----------+ | exam_id | student_id | score | +------------+--------------+-----------+ | 10 | 1 | 70 | | 10 | 2 | 80 | | 10 | 3 | 90 | | 20 | 1 | 80 | | 30 | 1 | 70 | | 30 | 3 | 80 | | 30 | 4 | 90 | | 40 | 1 | 60 | | 40 | 2 | 70 | | 40 | 4 | 80 | +------------+--------------+-----------+ Output: +-------------+---------------+ | student_id | student_name | +-------------+---------------+ | 2 | Jade | +-------------+---------------+ Explanation: For exam 1: Student 1 and 3 hold the lowest and high scores respectively. For exam 2: Student 1 hold both highest and lowest score. For exam 3 and 4: Studnet 1 and 4 hold the lowest and high scores respectively. Student 2 and 5 have never got the highest or lowest in any of the exams. Since student 5 is not taking any exam, he is excluded from the result. So, we only return the information of Student 2.