Subqueries

-- Select the names, hire date and salaries of the 10 highest paid employees
SELECT DISTINCT employees.emp_no,
        first_name,
        last_name,
        hire_date,
        salary
FROM employees
JOIN salaries
  on salaries.emp_no = employees.emp_no
WHERE employess.emp_no in (SELECT emp_no
                   FROM salaries
                  WHERE to_date >= CURDATE()
)

SELECT emp_no
FROM salaries
WHERE to_date >= CURDATE()
ORDER 
   BY salary desc
LIMIT 10