Zeta's assessment dashboard needs to display the strongest student results for every subject. Write a PostgreSQL query that returns the top two students in each subject from the students table.
score is NULL.student_id as the deterministic tie-breaker.| Column | Type | Description |
|---|---|---|
| student_idPK | INT | Unique student identifier |
| student_name | VARCHAR(100) | Student's name |
| subject | VARCHAR(50) | Assessment subject |
| score | INT | Assessment score |