How can you reference the department name from the outer query inside an inner query?

In SQL you can reference a column from the outer query inside an inner query by using a correlated subquery. The inner query can refer to columns of the outer query by simply naming them; the database engine will bind the outer values for each row processed. For example: SELECT d.dept_name, (SELECT COUNT() FROM employees e WHERE e.dept_id = d.dept_id AND e.status = 'active') AS active_count FROM departments d; Here the inner SELECT uses d.dept_id from the outer SELECT. The engine evaluates the inner query once per row of the outer result set, substituting the current dept_id value. This is useful when you need a per‑row aggregate or a conditional filter that depends on the outer row. If you need to filter the outer rows based on a condition that involves the inner query, you can use the EXISTS or IN predicate: SELECT d. FROM departments d WHERE EXISTS (SELECT 1 FROM employees e WHERE e.dept_id = d.dept_id AND e.status = 'active'); The key point is that the inner query can reference outer columns directly; you do not need to join explicitly. However, correlated subqueries can be slower than joins because they may execute repeatedly, so consider rewriting as a JOIN if performance is critical. In summary, you reference the outer column by name inside the inner query, and the database engine handles the binding automatically.