Exam 1z0-071 Topic 4 Question 392 Discussion

GROUP BY department _ id
Explanation:
To return all rows for employees whose salary is greater than the average salary in their department, you would use either a subquery or an analytic function:
Option B:
SELECT ... FROM employees WHERE salary > AVG(salary) OVER (PARTITION BY department_id); This uses the window function AVG with PARTITION BY to calculate the average salary per department, and it compares each employee's salary to this average.
Option C:
SELECT ... FROM employees e1 WHERE salary > (SELECT AVG(salary) FROM employees e2 WHERE e1.department_id = e2.department_id); This correlated subquery compares each employee's salary to the average salary in their department using a subquery to calculate the average salary for that department.
Options A, D, and E are incorrect because:
Option A: The use of ANY with the subquery does not ensure comparison with the average salary of their respective department.
Option D: This is syntactically incorrect; the subquery alias avg_sal is not accessible outside the subquery.
Option E: The subquery does not correlate with the outer query to ensure that each employee's salary is compared to the average salary of their respective department.