SQL Joins and Subqueries/Subquery in FROM

Use a derived table as a query source.

Section: Subqueries

Subquery in FROM

sql
sql
SELECT q.department_id, q.avg_salary
FROM (
  SELECT department_id, AVG(salary) AS avg_salary
  FROM employees
  GROUP BY department_id
) q;
Explanation

Derived tables let you treat nested query results as temporary relations.

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