leetcode刷題筆記一百八十四題 && 一百八十五題

阿新 • • 發佈：2020-09-14

源地址：

184問題描述：

Employee 表包含所有員工資訊，每個員工有其對應的 Id, salary 和 department Id。

+----+-------+--------+--------------+
| Id | Name | Salary | DepartmentId |
+----+-------+--------+--------------+
| 1 | Joe | 70000 | 1 |
| 2 | Jim | 90000 | 1 |
| 3 | Henry | 80000 | 2 |
| 4 | Sam | 60000 | 2 |
| 5 | Max | 90000 | 1 |
+----+-------+--------+--------------+
Department 表包含公司所有部門的資訊。

+----+----------+
| Id | Name |
+----+----------+
| 1 | IT |
| 2 | Sales |
+----+----------+
編寫一個 SQL 查詢，找出每個部門工資最高的員工。對於上述表，您的 SQL 查詢應返回以下行（行的順序無關緊要）。

+------------+----------+--------+
| Department | Employee | Salary |
+------------+----------+--------+
| IT | Max | 90000 |
| IT | Jim | 90000 |
| Sales | Henry | 80000 |
+------------+----------+--------+
解釋：

Max 和 Jim 在 IT 部門的工資都是最高的，Henry 在銷售部的工資最高。

# Write your MySQL query statement below
SELECT B.name AS 'Department',
    A.name AS 'Employee',
    Salary FROM Employee AS A JOIN Department B ON A.DepartmentId = B.Id 
WHERE  (A.DepartmentId , A.Salary) IN (
    SELECT DepartmentId, MAX(Salary) FROM Employee GROUP BY DepartmentId
);

185問題描述：

SQL架構

Employee 表包含所有員工資訊，每個員工有其對應的工號 Id，姓名 Name，工資 Salary 和部門編號 DepartmentId 。
+----+-------+--------+--------------+
| Id | Name  | Salary | DepartmentId |
+----+-------+--------+--------------+
| 1  | Joe   | 85000  | 1            |
| 2  | Henry | 80000  | 2            |
| 3  | Sam   | 60000  | 2            |
| 4  | Max   | 90000  | 1            |
| 5  | Janet | 69000  | 1            |
| 6  | Randy | 85000  | 1            |
| 7  | Will  | 70000  | 1            |
+----+-------+--------+--------------+
Department 表包含公司所有部門的資訊。
+----+----------+
| Id | Name     |
+----+----------+
| 1  | IT       |
| 2  | Sales    |
+----+----------+
編寫一個 SQL 查詢，找出每個部門獲得前三高工資的所有員工。例如，根據上述給定的表，查詢結果應返回：
+------------+----------+--------+
| Department | Employee | Salary |
+------------+----------+--------+
| IT         | Max      | 90000  |
| IT         | Randy    | 85000  |
| IT         | Joe      | 85000  |
| IT         | Will     | 70000  |
| Sales      | Henry    | 80000  |
| Sales      | Sam      | 60000  |
+------------+----------+--------+
解釋：

IT 部門中，Max 獲得了最高的工資，Randy 和 Joe 都拿到了第二高的工資，Will 的工資排第三。銷售部門（Sales）只有兩名員工，Henry 的工資最高，Sam 的工資排第二。

# Write your MySQL query statement below
SELECT B.Name AS Department, A.Name AS Employee,A.Salary FROM 
(SELECT dense_rank() OVER(PARTITION BY DepartmentId ORDER BY Salary DESC) AS RANKId, Name, Salary, DepartmentId FROM Employee) AS A JOIN Department AS B 
ON A.DepartmentId = B.Id WHERE A.RANKId <= 3;