The Employee table holds all employees. Every employee has an Id, and there is also a column for the department Id.
+----+-------+--------+--------------+
| Id | Name | Salary | DepartmentId |
+----+-------+--------+--------------+
| 1 | Joe | 70000 | 1 |
| 2 | Henry | 80000 | 2 |
| 3 | Sam | 60000 | 2 |
| 4 | Max | 90000 | 1 |
| 5 | Janet | 69000 | 1 |
| 6 | Randy | 85000 | 1 |
+----+-------+--------+--------------+The Department table holds all departments of the company.
+----+----------+
| Id | Name |
+----+----------+
| 1 | IT |
| 2 | Sales |
+----+----------+Write a SQL query to find employees who earn the top three salaries in each of the department. For the above
tables, your SQL query should return the following rows.
+------------+----------+--------+
| Department | Employee | Salary |
+------------+----------+--------+
| IT | Max | 90000 |
| IT | Randy | 85000 |
| IT | Joe | 70000 |
| Sales | Henry | 80000 |
| Sales | Sam | 60000 |
+------------+----------+--------+解决方式1
SELECT
d.Name AS Department, e.Name AS Employee, e.Salary
FROM
Employee e,
Department d
WHERE
e.DepartmentId = d.id
AND 3 > (SELECT
COUNT(DISTINCT (e2.Salary))
FROM
Employee e2
WHERE
e2.DepartmentId = d.id
AND e2.Salary > e.Salary)