MySQL练习题

DROP TABLE IF EXISTS `liuyan`;
CREATE TABLE `liuyan` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `title` varchar(32) NOT NULL,
  `author` varchar(16) DEFAULT NULL,
  `addtime` datetime DEFAULT NULL,
  `content` text,
  `isdelete` char(1) NOT NULL DEFAULT '0',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of liuyan
-- ----------------------------
INSERT INTO `liuyan` VALUES ('1', '介绍', '大雄', '2017-02-14 09:59:37', '哥不是一匹好马，但也不是一头普通的毛驴', '0');
INSERT INTO `liuyan` VALUES ('2', '叮当猫', '熊熊', '2016-02-16 09:59:44', '你牙缝里有韭菜，扣出来贼哥吃', '0');
INSERT INTO `liuyan` VALUES ('3', '花花', '苗苗', '2017-05-28 09:59:52', '苗苗问花花:卖萌是褒义词还是贬义词？', '0');
INSERT INTO `liuyan` VALUES ('4', '霞哥', '大雄', '2017-08-29 09:59:57', '斗战色佛', '0');
INSERT INTO `liuyan` VALUES ('5', '晨晨', '逗比', '2010-06-22 10:00:03', '你笑起来像一朵菊花,菊花残，man腚伤', '0');

...

练习题 一

1.创建留言数据库: liuyandb;

2.在liuyandb数据库中创建留言表liuyan，结构如下:

 

表名		liuyan		留言信息表
序号	字段名称	字段说明	类型	属性	备注
1	id	编号	int	非空	主键,自增1
2	title	标题	varchar(32)	非空
3	author	作者	varchar(16)	可以空
4	addtime	留言时间	datetime	非空
5	content	留言内容	text	非空
6	isdelete	是否删除	char(1)	非空	默认值

3.在留言表最后添加一列状态（status  char(1)  默认值为0）

4.修改留言表author的默认值为’youku’,设为非空

5.删除liuyan表中的isdelete字段

6.为留言表添加>5条测试数据 (例如:)

7. 要求将id值大于3的信息中author 字段值改为admin

8. 删除id号为4的数据。

 

附加题：

1. 为留言表添加>10条测试数据，要求分三个作者添加数据
2. 查询某一个作者的留言信息。
3. 查询所有数据，按时间降序排序。
4. 获取id在2到6之间的留言信息，并按时间降序排序
5. 统计每个作者留了多少条留言，并对数量按从小到大排序。
6. 将id为8、9的两条数据的作者改为’doudou’.
7. 取出最新的三条留言。
8. 查询留言者中包含”a”字母的留言信息，并按留言时间从小到大排序
9. 删除”作者”重复的数据,并保留id最大的一个作者

 

 1 -- truncate table 表名称 清空表
 2 -- drop table 表名 删除表
 3 
 4 
 5 2.
 6 create table liuyan(
 7     id int not null auto_increment PRIMARY KEY,
 8     title varchar(32) not NULL,
 9     author VARCHAR(16),
10     addtime datetime not null,
11     content text not null,
12     isdelete CHAR(1) not null
13 )
14 
15 3.
16 alter table liuyan add status char(1) DEFAULT 0;
17 
18 4.
19 alter table liuyan modify author VARCHAR(16) not null DEFAULT'youku';
20 
21 5.
22 alter table liuyan drop isdelete;
23 
24 6.
25 insert into liuyan VALUES(1,'机器猫','叮当猫','2012-12-12 12:12:12','我爱猫',0);
26 insert into liuyan VALUES(2,'小猫','大猫','2012-12-12 12:12:12','我爱猫',0);
27 insert into liuyan VALUES(3,'黑猫','白猫','2012-12-12 12:12:12','我爱猫',0);
28 insert into liuyan VALUES(4,'宠物猫','野猫','2012-12-12 12:12:12','我爱猫',0);
29 insert into liuyan VALUES(5,'外貌猫','抓鼠猫','2012-12-12','我爱猫',0);
30 
31 7.
32 UPDATE liuyan set author='admin' WHERE id>3;
33 
34 8.
35 DELETE FROM liuyan WHERE id=4;
36 
37 附加题1.
38 INSERT INTO `liuyan` VALUES ('6', '介绍', '大雄', '2017-02-14 09:59:37', '哥不是一匹好马，但也不是一头普通的毛驴', '0');
39 INSERT INTO `liuyan` VALUES ('7', '叮当猫', '熊熊', '2016-02-16 09:59:44', '你牙缝里有韭菜，扣出来贼哥吃', '0');
40 INSERT INTO `liuyan` VALUES ('8', '花花', '苗苗', '2017-05-28 09:59:52', '苗苗问花花:卖萌是褒义词还是贬义词？', '0');
41 INSERT INTO `liuyan` VALUES ('9', '霞哥', '大雄', '2017-08-29 09:59:57', '斗战色佛', '0');
42 INSERT INTO `liuyan` VALUES ('10', '晨晨', '逗比', '2010-06-22 10:00:03', '你笑起来像一朵菊花,菊花残，man腚伤', '0');
43 
44 2.
45 SELECT content FROM liuyan WHERE author='逗比';
46 
47 3.
48 SELECT * FROM liuyan ORDER BY addtime DESC;
49 
50 4.
51 select content,id from liuyan WHERE id BETWEEN 2 AND 6 ORDER BY addtime DESC;
52 
53 5.
54 ###
55 
56 6.
57 UPDATE liuyan set author='doudou' WHERE id in (8,9);
58 
59 7.
60 SELECT content,addtime FROM liuyan ORDER BY addtime desc HAVING ###
61 
62 8.
63 SELECT content FROM liuyan where content LIKE '%a%' ORDER BY addtime;
64 
65 9.
66 SELECT DISTINCT author from liuyan ###

答案

 练习题 二

 

1.查询所有人员信息

2.只查询人员的姓名和年龄

3.查询年龄为20岁的有哪些人员

4.查询60岁以下的人员有哪些人员

5.查询50岁以上并且工资大于8000的人员有哪些

6.查询姓[张]的人员有哪些

7.查询哪些人员属于 武当/华山/嵩山

8.查询工资在 5000-8900 的人员有哪些

9.查询所有人员,要求按工资倒序排列

10.查询令狐冲的领导人是谁

11.查询人员表中最高工资是多少

12.查询人员表中最低工资是多少

13.查询所有人员的平均工资是多少

14.查询所有人员的工资总和是多少

15.查询目前有多少个人员

16.查询当前武林中有哪些门派

17.查询 武当派 最高工资是谁

18.查询各门派的平均工资是多少

19.查询当前武林中有哪些门派的平均工资大于8000 并按工资倒序排列

20.查询当前人员表的中的第3条数据到第7条数据

21.查询哪些门派下没有弟子

22.查询武当派下有哪些弟子

23.查询各门派的工资总和按倒序/正序排列

24.删除工资重复的人员,请保留年龄最大的一个人

25.将武当派 张三丰 修改为 张丰

26.将所有门派大哥工资上调10%,但不包括Alex.

27.查看哪些人员的门派已登记地理位置.

28.查询所有人员门派的位置信息,不存在位置信息则不显示

29.在湖北省内的门派中的人员有哪些.

30.在陕西省内门派中的工资小于5000,年龄大于20岁的人员有哪些,按主键倒序排列

CREATE TABLE person(
    id int auto_increment PRIMARY KEY,
    name VARCHAR(10) not null,
    age int,
    salary int,
    leader int,
    menpai VARCHAR(16)
)

CREATE TABLE dept(
    did int auto_increment PRIMARY KEY,
    dname VARCHAR(10),
    address VARCHAR(10)
)

1.
SELECT * from person;

2.
SELECT name,age from person;

3.
SELECT name from person WHERE age=20;

4.
SELECT name,age from person WHERE age<60;

5.
SELECT name from person WHERE age>5000 and salary>8000;

6.
SELECT name from person WHERE name like '张%';

7.
SELECT name,menpai from person WHERE menpai in ('武当','华山','嵩山');

8.
SELECT name,salary from person WHERE salary between 5000 and 8900;

9.
SELECT * from person ORDER BY salary desc;

10.
SELECT leader from person WHERE name='令狐冲';

11.
SELECT max(salary) from person
select name from person WHERE salary=(SELECT max(salary) from person);

12.
select name,min(salary) from person;

13.
SELECt avg(salary) from person;

14.
select sum(salary) from person;

15.
select count(name) from person;

16.
select menpai from person GROUP BY menpai;

17.
select name from person WHERE menpai='武当' GROUP BY menpai HAVING max(salary);
select max(salary) from person WHERE name in(select name from person WHERE menpai='武当')

18.
select menpai,avg(salary) from person GROUP BY menpai;

19.
select menpai,avg(salary) from person GROUP BY menpai HAVING avg(salary)>8000 ORDER BY salary desc;

20.
select * from person limit 2,5;

21.


22.
select name from person WHERE menpai='武当';

23.
select menpai,sum(salary) from person GROUP BY menpai;

24.
SELECT DISTINCT(salary) from person WHERE age=(select max(age) from person)

25.
UPDATE person set name='张三丰' WHERE name='张丰';

26.
select salary*1.1 from person WHERE name != 'alex';

27.
select menpai from person,dept WHERE person.menpai=dept.dname;

28.
select * from person,dept WHERE person.menpai=dept.dname;

29.
select name from person,dept WHERE person.menpai=dept.dname and address='湖北';

30.
select name from person,dept WHERE person.menpai=dept.dname and address='陕西' and age>20 and salary<5000;

答案

练习题三

1.创建表和数据

-- 创建数据表
  CREATE TABLE IF NOT EXISTS tdb_goods(
    goods_id    SMALLINT UNSIGNED PRIMARY KEY AUTO_INCREMENT, -- 商品主键
    goods_name  VARCHAR(150) NOT NULL,    -- 商品名称
    goods_cate  VARCHAR(40)  NOT NULL,    -- 商品类型
    brand_name  VARCHAR(40)  NOT NULL,  -- 商品品牌
    goods_price DECIMAL(15,3) UNSIGNED NOT NULL DEFAULT 0, -- 商品价格
    is_show     BOOLEAN NOT NULL DEFAULT 1,    -- 是否上架
    is_saleoff  BOOLEAN NOT NULL DEFAULT 0    -- 是否打折
  );

 -- 写入记录

 INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff) VALUES('R510VC 15.6英寸笔记本','笔记本','华硕','3399',DEFAULT,DEFAULT);
 
 INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff) VALUES('Y400N 14.0英寸笔记本电脑','笔记本','联想','4899',DEFAULT,DEFAULT);
 
 INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff) VALUES('G150TH 15.6英寸游戏本','游戏本','雷神','8499',DEFAULT,DEFAULT);
 
 INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff) VALUES('X550CC 15.6英寸笔记本','笔记本','华硕','2799',DEFAULT,DEFAULT);
 
 INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff) VALUES('X240(20ALA0EYCD) 12.5英寸超极本','超级本','联想','4999',DEFAULT,DEFAULT);
 
 INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff) VALUES('U330P 13.3英寸超极本','超级本','联想','4299',DEFAULT,DEFAULT);
 
 INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff) VALUES('SVP13226SCB 13.3英寸触控超极本','超级本','索尼','7999',DEFAULT,DEFAULT);
 
 INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff) VALUES('iPad mini MD531CH/A 7.9英寸平板电脑','平板电脑','苹果','1998',DEFAULT,DEFAULT);
 
 INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff) VALUES('iPad Air MD788CH/A 9.7英寸平板电脑 （16G WiFi版）','平板电脑','苹果','3388',DEFAULT,DEFAULT);
 
 INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff) VALUES(' iPad mini ME279CH/A 配备 Retina 显示屏 7.9英寸平板电脑 （16G WiFi版）','平板电脑','苹果','2788',DEFAULT,DEFAULT);
 
 INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff) VALUES('IdeaCentre C340 20英寸一体电脑 ','台式机','联想','3499',DEFAULT,DEFAULT);
 
 INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff) VALUES('Vostro 3800-R1206 台式电脑','台式机','戴尔','2899',DEFAULT,DEFAULT);
 
 INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff) VALUES('iMac ME086CH/A 21.5英寸一体电脑','台式机','苹果','9188',DEFAULT,DEFAULT);
 
 INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff) VALUES('AT7-7414LP 台式电脑 （i5-3450四核 4G 500G 2G独显 DVD 键鼠 Linux ）','台式机','宏碁','3699',DEFAULT,DEFAULT);
 
 INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff) VALUES('Z220SFF F4F06PA工作站','服务器/工作站','惠普','4288',DEFAULT,DEFAULT);
 
 INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff) VALUES('PowerEdge T110 II服务器','服务器/工作站','戴尔','5388',DEFAULT,DEFAULT);
 
 INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff) VALUES('Mac Pro MD878CH/A 专业级台式电脑','服务器/工作站','苹果','28888',DEFAULT,DEFAULT);
 
 INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff) VALUES(' HMZ-T3W 头戴显示设备','笔记本配件','索尼','6999',DEFAULT,DEFAULT);

 INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff) VALUES('商务双肩背包','笔记本配件','索尼','99',DEFAULT,DEFAULT);

 INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff) VALUES('X3250 M4机架式服务器 2583i14','服务器/工作站','IBM','6888',DEFAULT,DEFAULT);
 
 INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff) VALUES('玄龙精英版 笔记本散热器','笔记本配件','九州风神','',DEFAULT,DEFAULT);

 INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff) VALUES(' HMZ-T3W 头戴显示设备','笔记本配件','索尼','6999',DEFAULT,DEFAULT);

 INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff) VALUES('商务双肩背包','笔记本配件','索尼','99',DEFAULT,DEFAULT);

创建表和数据

2. 求所有电脑产品的平均价格,并且保留两位小数，AVG,MAX,MIN,COUNT,SUM为聚合函数

3.查询所有价格大于平均价格的商品，并且按价格降序排序

4.查询类型为“超级本”的商品价格

5.查询价格等于"超级本"价格的商品，并且按价格降序排列

6.创建“商品类别”表

7.查询tdb_goods表的类别记录，并且按"类别"分组

8.将分组结果写入到tdb_goods_cates数据表

9.通过tdb_goods_cates数据表来更新tdb_goods表中的'类别字段'

10.通过CREATE...SELECT来 创建[品牌]表 并且同时写入记录

11.通过tdb_goods_brands 品牌表 来更新 tdb_goods商品表

12.查看tdb_goods的数据表结构

13.通过ALTER TABLE语句修改商品表结构,goods_cate更新为cate_id, brand_name更新为brand_id

14.分别在tdb_goods_cates(类别表)和tdb_goods_brands(品牌表)插入记录

15.在tdb_goods数据表写入任意记录

16.查询所有商品的详细信息(通过内连接实现)

17.查询所有商品的详细信息(通过左外连接实现)

18.查询所有商品的详细信息(通过右外连接实现)

19.无限分类的数据表设计

20.查找所有分类及其父类(将自身作为临时表使用)

21. 复制编号为12,20的两条记录

22.查找重复记录

23. 删除重复记录 

2.
select avg(goods_price) from tdb_goods;

3.
select goods_name,goods_price from tdb_goods WHERE goods_price > (select avg(goods_price) from tdb_goods) ORDER BY goods_price DESC;

4.
SELECT goods_price from tdb_goods WHERE goods_cate = '超级本';

5.
SELECT goods_name,goods_price from tdb_goods WHERE goods_price in (SELECT goods_price from tdb_goods WHERE goods_cate = '超级本') ORDER BY goods_price DESC;

6.
CREATE TABLE IF NOT EXISTS tdb_goods_cates(
 
    cate_id SMALLINT UNSIGNED PRIMARY KEY AUTO_INCREMENT,
     
    cate_name VARCHAR(40)
 
  );

7.
select goods_cate from tdb_goods GROUP BY goods_cate;

8.
insert into tdb_goods_cates(cate_name) select  goods_cate from tdb_goods GROUP BY goods_cate;

9.
select * from tdb_goods inner JOIN tdb_goods_cates on tdb_goods.goods_cate = tdb_goods_cates.cate_name;

UPDATE tdb_goods INNER JOIN tdb_goods_cates on tdb_goods.goods_cate = tdb_goods_cates.cate_name set goods_cate = cate_id;

10.
select brand_name from tdb_goods GROUP BY brand_name;

CREATE table tdb_goods_brands(
    brand_id int PRIMARY KEY auto_increment,
    brand_name VARCHAR(20) not null
) SELECT brand_name from tdb_goods GROUP BY brand_name;


11.
UPDATE tdb_goods inner JOIN tdb_goods_brands on tdb_goods.brand_name = tdb_goods_brands.brand_name set tdb_goods.brand_name = tdb_goods_brands.brand_id;

12.
desc tdb_goods;

13.
ALTER TABLE tdb_goods change goods_cate cate_id int not null,
change brand_name brand_id int not null;

14.
INSERT tdb_goods_cates(cate_name) VALUES('路由器'),('交换机'),('网卡');
INSERT tdb_goods_brands(brand_name) VALUES('海尔'),('清华同方'),('神舟');

15.
INSERT tdb_goods(goods_name,cate_id,brand_id,goods_price) VALUES('LaserJet Pro P1606dn 黑白激光打印机','12','4','1849');

16.
SELECT goods_id,goods_name,goods_price,cate_name,brand_name from tdb_goods as t1
inner JOIN tdb_goods_cates as t2 on t1.cate_id = t2.cate_id
inner JOIN tdb_goods_brands as t3 on t1.brand_id = t3.brand_id;

17.
select goods_id,goods_name,goods_price,cate_name,brand_name from tdb_goods as t1
LEFT JOIN tdb_goods_cates as t2 on t1.cate_id = t2.cate_id
LEFT JOIN tdb_goods_brands as t3 on t1.brand_id = t3.brand_id;

18.
select goods_id,goods_name,goods_price,cate_name,brand_name from tdb_goods as t1
RIGHT JOIN tdb_goods_cates as t2 on t1.cate_id = t2.cate_id
RIGHT JOIN tdb_goods_brands as t3 on t1.brand_id = t3.brand_id;

19.
CREATE TABLE tdb_goods_types(
   type_id   SMALLINT UNSIGNED PRIMARY KEY AUTO_INCREMENT,
   type_name VARCHAR(20) NOT NULL,
   parent_id SMALLINT UNSIGNED NOT NULL DEFAULT 0
);

INSERT tdb_goods_types(type_name,parent_id) VALUES('家用电器',DEFAULT);
INSERT tdb_goods_types(type_name,parent_id) VALUES('电脑、办公',DEFAULT);
INSERT tdb_goods_types(type_name,parent_id) VALUES('大家电',1);
INSERT tdb_goods_types(type_name,parent_id) VALUES('生活电器',1);
INSERT tdb_goods_types(type_name,parent_id) VALUES('平板电视',3);
INSERT tdb_goods_types(type_name,parent_id) VALUES('空调',3);
INSERT tdb_goods_types(type_name,parent_id) VALUES('电风扇',4);
INSERT tdb_goods_types(type_name,parent_id) VALUES('饮水机',4);
INSERT tdb_goods_types(type_name,parent_id) VALUES('电脑整机',2);
INSERT tdb_goods_types(type_name,parent_id) VALUES('电脑配件',2);
INSERT tdb_goods_types(type_name,parent_id) VALUES('笔记本',9);
INSERT tdb_goods_types(type_name,parent_id) VALUES('超级本',9);
INSERT tdb_goods_types(type_name,parent_id) VALUES('游戏本',9);
INSERT tdb_goods_types(type_name,parent_id) VALUES('CPU',10);
INSERT tdb_goods_types(type_name,parent_id) VALUES('主机',10);

20.
select * FROM tdb_goods_types p1;
select * FROM tdb_goods_types p2;
 
SELECT p1.type_id,p1.type_name,p2.type_name as '父类'
    FROM tdb_goods_types p1 LEFT JOIN tdb_goods_types p2
on p1.parent_id = p2.type_id

21.
SELECT * FROM tdb_goods WHERE goods_id IN (19,20);
 
-- INSERT ... SELECT实现复制
 
INSERT tdb_goods(goods_name,cate_id,brand_id) SELECT goods_name,cate_id,brand_id FROM tdb_goods WHERE goods_id IN (19,20);

22.
SELECT goods_id,goods_name FROM tdb_goods
   GROUP BY goods_name HAVING count(goods_name) >= 2;
     
23.
#方式一:
  1.查询重复记录,获得重复字段
　　SELECT goods_name FROM tdb_goods ROUP BY goods_name HAVING count(goods_name) >= 2
   
  2.通过重复字段进行删除
    -- 错误
    DELETE FROM tdb_goods WHERE goods_name in(SELECT goods_name FROM tdb_goods
    GROUP BY goods_name HAVING count(goods_name) >= 2)
     
    -- [Err] 1093 - You can't specify target table 'tdb_goods' for update in FROM clause
    -- 不能在同一个表中即查询数据又删除数据
 
    -- 正确
    DELETE FROM tdb_goods WHERE goods_name in(SELECT * from (SELECT goods_name FROM tdb_goods
        GROUP BY goods_name HAVING count(goods_name) >= 2)as 别名)
    注意: 使用临时表 将子查询包裹,并起个别名
 
#方式二:保留一条
    DELETE FROM tdb_goods WHERE goods_name in(SELECT * from (SELECT goods_name FROM tdb_goods
        GROUP BY goods_name HAVING count(goods_name) >= 2)as ss)
    and goods_id not in(SELECT * from (SELECT goods_id FROM tdb_goods
        GROUP BY goods_name HAVING count(goods_name) >= 2)as 别名)

答案

练习题四

#课程表
CREATE TABLE `course` (
  `c_id` int(11) NOT NULL,
  `c_name` varchar(50) DEFAULT NULL,
  `t_id` int(11) DEFAULT NULL,
  PRIMARY KEY (`c_id`),
  KEY `t_id` (`t_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

INSERT INTO `course` VALUES ('1', 'python', '1');
INSERT INTO `course` VALUES ('2', 'java', '2');
INSERT INTO `course` VALUES ('3', 'linux', '3');
INSERT INTO `course` VALUES ('4', 'web', '2');

#成绩表
CREATE TABLE `score` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `s_id` int(11) DEFAULT NULL,
  `c_id` int(11) DEFAULT NULL,
  `num` double DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=12 DEFAULT CHARSET=utf8;

INSERT INTO `score` VALUES ('1', '1', '1', '79');
INSERT INTO `score` VALUES ('2', '1', '2', '78');
INSERT INTO `score` VALUES ('3', '1', '3', '35');
INSERT INTO `score` VALUES ('4', '2', '2', '32');
INSERT INTO `score` VALUES ('5', '3', '1', '66');
INSERT INTO `score` VALUES ('6', '4', '2', '77');
INSERT INTO `score` VALUES ('7', '4', '1', '68');
INSERT INTO `score` VALUES ('8', '5', '1', '66');
INSERT INTO `score` VALUES ('9', '2', '1', '69');
INSERT INTO `score` VALUES ('10', '4', '4', '75');
INSERT INTO `score` VALUES ('11', '5', '4', '66.7');

#学生表
CREATE TABLE `student` (
  `s_id` varchar(20) NOT NULL,
  `s_name` varchar(50) DEFAULT NULL,
  `s_age` int(10) DEFAULT NULL,
  `s_sex` char(1) DEFAULT NULL,
  PRIMARY KEY (`s_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

INSERT INTO `student` VALUES ('1', '鲁班', '12', '男');
INSERT INTO `student` VALUES ('2', '貂蝉', '20', '女');
INSERT INTO `student` VALUES ('3', '刘备', '35', '男');
INSERT INTO `student` VALUES ('4', '关羽', '34', '男');
INSERT INTO `student` VALUES ('5', '张飞', '33', '女');

#老师表
CREATE TABLE `teacher` (
  `t_id` int(10) NOT NULL,
  `t_name` varchar(50) DEFAULT NULL,
  PRIMARY KEY (`t_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

INSERT INTO `teacher` VALUES ('1', '大王');
INSERT INTO `teacher` VALUES ('2', 'alex');
INSERT INTO `teacher` VALUES ('3', 'egon');
INSERT INTO `teacher` VALUES ('4', 'peiqi');

数据脚本

查询以下题目:

1. 查询学习课程"python"比课程 "java" 成绩高的学生的学号;
2. 查询平均成绩大于65分的同学的姓名和平均成绩(保留两位小数);　　
3. 查询所有同学的姓名、选课数、总成绩；
4. 查询所有的课程的名称以及对应的任课老师姓名;
5. 查询没学过“alex”老师课的同学的姓名;
6. 查询学过'python'并且也学过编号'java'课程的同学的姓名;
7. 查询学过“alex”老师所教的全部课程的同学的姓名；
8. 查询挂科超过两门(包括两门)的学生姓名;
9. 查询有课程成绩小于60分的同学的姓名;
10. 查询选修了全部课程的学生姓名;
11. 查询至少有一门课程与“貂蝉”同学所学课程相同的同学姓名；
12. 查询学过'貂蝉'同学全部课程 的其他同学姓名；
13. 查询和'貂蝉'同学学习的课程完全相同的,其他同学姓名；
14. 按平均成绩倒序显示所有学生的“python”、“java”、“linux”三门的课程成绩，按如下形式显示： 学生ID,python,java,linux,课程数,平均分
15. 统计各科各分数段人数.显示格式:课程ID,课程名称,[100-85],[85-70],[70-60],[ <60] 
16. 查询每门课程被选修的次数
17. 查询出只选修了一门课程的学生的学号和姓名
18. 查询学生表中男生、女生各有多少人
19. 查询每门课程的平均成绩，结果按平均成绩升序排列，平均成绩相同时，按课程号降序排列
20. 查询课程名称为“python”，且分数低于60的学生姓名和分数

 

转载于:https://www.cnblogs.com/ys-python/p/10907649.html