删除部分题目
This commit is contained in:
mba1398
GitHub
parent
04c4b1b6a2
commit
31c64da7cc
282
ch06:决胜秋招.md
282
ch06:决胜秋招.md
|
|
@ -8,81 +8,7 @@
|
|||
|
||||
## Section A
|
||||
|
||||
### 练习一: 各部门工资最高的员工（难度：中等）
|
||||
|
||||
创建Employee 表，包含所有员工信息，每个员工有其对应的 Id, salary 和 department Id。
|
||||
|
||||
```plain
|
||||
+----+-------+--------+--------------+
|
||||
| Id | Name | Salary | DepartmentId |
|
||||
+----+-------+--------+--------------+
|
||||
| 1 | Joe | 70000 | 1 |
|
||||
| 2 | Henry | 80000 | 2 |
|
||||
| 3 | Sam | 60000 | 2 |
|
||||
| 4 | Max | 90000 | 1 |
|
||||
+----+-------+--------+--------------+
|
||||
```
|
||||
创建Department 表，包含公司所有部门的信息。
|
||||
```plain
|
||||
+----+----------+
|
||||
| Id | Name |
|
||||
+----+----------+
|
||||
| 1 | IT |
|
||||
| 2 | Sales |
|
||||
+----+----------+
|
||||
```
|
||||
编写一个 SQL 查询，找出每个部门工资最高的员工。例如，根据上述给定的表格，Max 在 IT 部门有最高工资，Henry 在 Sales 部门有最高工资。
|
||||
```plain
|
||||
+------------+----------+--------+
|
||||
| Department | Employee | Salary |
|
||||
+------------+----------+--------+
|
||||
| IT | Max | 90000 |
|
||||
| Sales | Henry | 80000 |
|
||||
+------------+----------+--------+
|
||||
```
|
||||
|
||||
### 练习二: 换座位（难度：中等）
|
||||
|
||||
小美是一所中学的信息科技老师，她有一张 seat 座位表，平时用来储存学生名字和与他们相对应的座位 id。
|
||||
|
||||
其中纵列的**id**是连续递增的
|
||||
|
||||
小美想改变相邻俩学生的座位。
|
||||
|
||||
你能不能帮她写一个 SQL query 来输出小美想要的结果呢？
|
||||
|
||||
请创建如下所示seat表：
|
||||
|
||||
**示例：**
|
||||
|
||||
```plain
|
||||
+---------+---------+
|
||||
| id | student |
|
||||
+---------+---------+
|
||||
| 1 | Abbot |
|
||||
| 2 | Doris |
|
||||
| 3 | Emerson |
|
||||
| 4 | Green |
|
||||
| 5 | Jeames |
|
||||
+---------+---------+
|
||||
```
|
||||
假如数据输入的是上表，则输出结果如下：
|
||||
```plain
|
||||
+---------+---------+
|
||||
| id | student |
|
||||
+---------+---------+
|
||||
| 1 | Doris |
|
||||
| 2 | Abbot |
|
||||
| 3 | Green |
|
||||
| 4 | Emerson |
|
||||
| 5 | Jeames |
|
||||
+---------+---------+
|
||||
```
|
||||
**注意：**
|
||||
如果学生人数是奇数，则不需要改变最后一个同学的座位。
|
||||
|
||||
|
||||
### 练习三: 分数排名（难度：中等）
|
||||
### 练习一: 分数排名（难度：中等）
|
||||
|
||||
假设在某次期末考试中，二年级四个班的平均成绩分别是 `93、93、93、91`。
|
||||
|
||||
|
|
@ -109,212 +35,6 @@
|
|||
+-------+-----------+-------+-------+-------+
|
||||
```
|
||||
|
||||
### 练习四：连续出现的数字（难度：中等）
|
||||
|
||||
编写一个 SQL 查询，查找所有至少连续出现三次的数字。
|
||||
|
||||
```plain
|
||||
+----+-----+
|
||||
| Id | Num |
|
||||
+----+-----+
|
||||
| 1 | 1 |
|
||||
| 2 | 1 |
|
||||
| 3 | 1 |
|
||||
| 4 | 2 |
|
||||
| 5 | 1 |
|
||||
| 6 | 2 |
|
||||
| 7 | 2 |
|
||||
+----+-----+
|
||||
```
|
||||
例如，给定上面的 Logs 表， 1 是唯一连续出现至少三次的数字。
|
||||
```plain
|
||||
+-----------------+
|
||||
| ConsecutiveNums |
|
||||
+-----------------+
|
||||
| 1 |
|
||||
+-----------------+
|
||||
```
|
||||
### 练习五：树节点 （难度：中等）
|
||||
|
||||
对于**tree**表，*id*是树节点的标识，*p_id*是其父节点的*id*。
|
||||
|
||||
```plain
|
||||
+----+------+
|
||||
| id | p_id |
|
||||
+----+------+
|
||||
| 1 | null |
|
||||
| 2 | 1 |
|
||||
| 3 | 1 |
|
||||
| 4 | 2 |
|
||||
| 5 | 2 |
|
||||
+----+------+
|
||||
```
|
||||
每个节点都是以下三种类型中的一种：
|
||||
* Root: 如果节点是根节点。
|
||||
* Leaf: 如果节点是叶子节点。
|
||||
* Inner: 如果节点既不是根节点也不是叶子节点。
|
||||
|
||||
写一条查询语句打印节点id及对应的节点类型。按照节点id排序。上面例子的对应结果为：
|
||||
|
||||
```plain
|
||||
+----+------+
|
||||
| id | Type |
|
||||
+----+------+
|
||||
| 1 | Root |
|
||||
| 2 | Inner|
|
||||
| 3 | Leaf |
|
||||
| 4 | Leaf |
|
||||
| 5 | Leaf |
|
||||
+----+------+
|
||||
```
|
||||
**说明**
|
||||
* 节点’1’是根节点，因为它的父节点为NULL，有’2’和’3’两个子节点。
|
||||
* 节点’2’是内部节点，因为它的父节点是’1’，有子节点’4’和’5’。
|
||||
* 节点’3’，‘4’，'5’是叶子节点，因为它们有父节点但没有子节点。
|
||||
|
||||
下面是树的图形：
|
||||
|
||||
1
|
||||
/ \
|
||||
2 3
|
||||
/ \
|
||||
4 5
|
||||
|
||||
**注意**
|
||||
|
||||
如果一个树只有一个节点，只需要输出根节点属性。
|
||||
|
||||
### 练习六：至少有五名直接下属的经理 （难度：中等）
|
||||
|
||||
**Employee**表包含所有员工及其上级的信息。每位员工都有一个Id，并且还有一个对应主管的Id（ManagerId）。
|
||||
|
||||
```plain
|
||||
+------+----------+-----------+----------+
|
||||
|Id |Name |Department |ManagerId |
|
||||
+------+----------+-----------+----------+
|
||||
|101 |John |A |null |
|
||||
|102 |Dan |A |101 |
|
||||
|103 |James |A |101 |
|
||||
|104 |Amy |A |101 |
|
||||
|105 |Anne |A |101 |
|
||||
|106 |Ron |B |101 |
|
||||
+------+----------+-----------+----------+
|
||||
```
|
||||
针对**Employee**表，写一条SQL语句找出至少有5个下属的主管。对于上面的表，结果应输出：
|
||||
|
||||
```plain
|
||||
+-------+
|
||||
| Name |
|
||||
+-------+
|
||||
| John |
|
||||
+-------+
|
||||
```
|
||||
**注意:**
|
||||
|
||||
没有人向自己汇报。
|
||||
|
||||
### 练习七：各部门前3高工资的员工（难度：中等）
|
||||
|
||||
将练习一中的 `employee` 表清空，重新插入以下数据（也可以复制练习一中的 `employee` 表，再插入第5、第6行数据）：
|
||||
|
||||
```plain
|
||||
+----+-------+--------+--------------+
|
||||
| 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 |
|
||||
+----+-------+--------+--------------+
|
||||
```
|
||||
编写一个 SQL 查询，找出每个部门工资前三高的员工。例如，根据上述给定的表格，查询结果应返回：
|
||||
```plain
|
||||
+------------+----------+--------+
|
||||
| Department | Employee | Salary |
|
||||
+------------+----------+--------+
|
||||
| IT | Max | 90000 |
|
||||
| IT | Randy | 85000 |
|
||||
| IT | Joe | 70000 |
|
||||
| Sales | Henry | 80000 |
|
||||
| Sales | Sam | 60000 |
|
||||
+------------+----------+--------+
|
||||
```
|
||||
此外，请考虑实现各部门前N高工资的员工功能。
|
||||
|
||||
### 练习八：平面上最近距离 (难度: 困难）
|
||||
|
||||
**point_2d**表包含一个平面内一些点（超过两个）的坐标值（x，y）。
|
||||
|
||||
写一条查询语句求出这些点中的最短距离并保留2位小数。
|
||||
|
||||
```plain
|
||||
|x | y |
|
||||
|----|----|
|
||||
| -1 | -1 |
|
||||
| 0 | 0 |
|
||||
| -1 | -2 |
|
||||
```
|
||||
最短距离是1，从点（-1，-1）到点（-1，-2）。所以输出结果为：
|
||||
|
||||
| shortest |
|
||||
|
||||
1.00
|
||||
|
||||
```plain
|
||||
+--------+
|
||||
|shortest|
|
||||
+--------+
|
||||
|1.00 |
|
||||
+--------+
|
||||
```
|
||||
**注意：**所有点的最大距离小于10000。
|
||||
|
||||
### 练习九：行程和用户（难度：困难）
|
||||
|
||||
Trips 表中存所有出租车的行程信息。每段行程有唯一键 Id，Client_Id 和 Driver_Id 是 Users 表中 Users_Id 的外键。Status 是枚举类型，枚举成员为 (‘completed’, ‘cancelled_by_driver’, ‘cancelled_by_client’)。
|
||||
|
||||
| Id | Client_Id | Driver_Id | City_Id | Status |Request_at|
|
||||
|:----|:----|:----|:----|:----|:----|
|
||||
|1|1|10|1| completed |2013-10-1|
|
||||
|2|2|11|1| cancelled_by_driver|2013-10-1|
|
||||
|3|3|12|6| completed |2013-10-1|
|
||||
|4|4|13|6| cancelled_by_client|2013-10-1|
|
||||
|5|1|10|1| completed |2013-10-2|
|
||||
|6|2|11|6| completed |2013-10-2|
|
||||
|7|3|12|6| completed |2013-10-2|
|
||||
|8|2|12|12| completed |2013-10-3|
|
||||
|9|3|10|12| completed |2013-10-3|
|
||||
|10|4|13|12| cancelled_by_driver|2013-10-3|
|
||||
|
||||
Users 表存所有用户。每个用户有唯一键 Users_Id。Banned 表示这个用户是否被禁止，Role 则是一个表示（‘client’, ‘driver’, ‘partner’）的枚举类型。
|
||||
|
||||
```plain
|
||||
+----------+--------+--------+
|
||||
| Users_Id | Banned | Role |
|
||||
+----------+--------+--------+
|
||||
| 1 | No | client |
|
||||
| 2 | Yes | client |
|
||||
| 3 | No | client |
|
||||
| 4 | No | client |
|
||||
| 10 | No | driver |
|
||||
| 11 | No | driver |
|
||||
| 12 | No | driver |
|
||||
| 13 | No | driver |
|
||||
+----------+--------+--------+
|
||||
```
|
||||
写一段 SQL 语句查出**2013年10月1日**至**2013年10月3日**期间非禁止用户的取消率。基于上表，你的 SQL 语句应返回如下结果，取消率（Cancellation Rate）保留两位小数。
|
||||
```plain
|
||||
+------------+-------------------+
|
||||
| Day | Cancellation Rate |
|
||||
+------------+-------------------+
|
||||
| 2013-10-01 | 0.33 |
|
||||
| 2013-10-02 | 0.00 |
|
||||
| 2013-10-03 | 0.50 |
|
||||
+------------+-------------------+
|
||||
```
|
||||
|
||||
## Section B
|
||||
|
||||
### 练习一：行转列
|
||||
|
|
|
|||
Loading…
Reference in New Issue