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Top N Students by Subject

MediumSQL · PostgreSQL00:00
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Your question is Top N Students by Subject. Start with the requirements and the three tables on the right.

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Problem

How would you retrieve the top N students for a given subject?

Write a PostgreSQL query against the students, subjects, and student_scores tables. For this exercise, use Mathematics as the subject and return the top 3 students. Scores that are NULL must be ignored.

Output

  1. One row per qualifying student, with student_id, student_name, subject_name, score, and position.
  2. Include only the requested subject and the top 3 positions.
  3. Order by position ascending. Break equal scores by lower student_id.

Schema

students
ColumnTypeDescription
student_idPKINTEGERUnique student identifier
student_nameVARCHAR(100)Student full name
subjects
ColumnTypeDescription
subject_idPKINTEGERUnique subject identifier
subject_nameVARCHAR(100)Subject name
student_scores
ColumnTypeDescription
score_idPKINTEGERUnique score record identifier
student_idINTEGERReferenced student identifier
subject_idINTEGERReferenced subject identifier
scoreNUMERIC(5,2)Student score for the subject
Tablesstudentssubjectsstudent_scores
Your solutionPostgreSQL
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