SQL Above Class Average | Dataford Interview Questions

Your question is SQL Above Class Average. Start with the requirements and the two tables on the right.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem

Ericsson is reviewing results from an internal data engineering class. Write a PostgreSQL query to identify trainees whose grade is strictly higher than the class average.

The class average must be calculated from all non-NULL grades in student_grades. Include only students with a recorded grade above that average.

Requirements

Calculate the overall class average using AVG, allowing PostgreSQL to ignore NULL grades.
Return the student ID, student name, grade, and rounded class average.
Exclude students whose grade is NULL or equal to the class average.
Sort the results by grade descending, then student ID ascending for ties.

Schema

students

Column	Type	Description
student_idPK	INTEGER	Unique trainee identifier
student_name	VARCHAR(100)	Trainee's full name

student_grades

Column	Type	Description
student_idPK	INTEGER	Trainee identifier referencing students.student_id
grade	NUMERIC(5,2)	Class grade from 0 to 100