In SQL code, how would you write a query to find the second highest salary?

To find the second highest salary in a table, you can use a subquery or a window function. Using a subquery:

SELECT MAX(salary) AS second_highest
FROM employees
WHERE salary < (SELECT MAX(salary) FROM employees);

This returns the largest salary that is less than the overall maximum. If there are duplicate top salaries, this still works because it excludes all rows equal to the maximum. Alternatively, with a window function:

SELECT salary
FROM (
  SELECT salary,
         DENSE_RANK() OVER (ORDER BY salary DESC) AS rnk
  FROM employees
) AS ranked
WHERE rnk = 2;

Both approaches run in O(n) time, scanning the table once. The window‑function version is more flexible if you need to retrieve additional columns or handle ties. Choose the one that aligns with your database’s performance characteristics.