DENSE_RANK分析函数的使用

SELECT

  department_id,

  first_name||' '||last_name employee_name,

  hire_date,

  salary,

  MIN(salary) KEEP (DENSE_RANK FIRST ORDER BY hire_date) OVER (PARTITION BY department_id) "Worst",

  MAX(salary) KEEP (DENSE_RANK LAST ORDER BY hire_date) OVER (PARTITION BY department_id) "Best"

FROM employees