Question

这用于子查询。但我需要使用join

select first_name,department_id,salary from employees
where (department_id , salary) in (select department_id ,max (salary) as max_sal from employees
group by department_id);

Answer 1

抱歉，没有子查询，你就无法拥有它。但是，您可以使用联接代替IN运算符：

SELECT
  e.first_name AS first_name,
  e.department_id AS department_id,
  e.salary AS salary
FROM
 employees e
 JOIN (
   SELECT department_id, MAX(salary) AS salary
   FROM employees
   GROUP BY department_id
 ) e_max
   ON e.department_id = e_max.department_id AND e.salary = e_max.salary

如何使用join而不是group by来查找多列？

1 个答案: