

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:
- 为留言表添加>10条测试数据,要求分三个作者添加数据
- 查询某一个作者的留言信息。
- 查询所有数据,按时间降序排序。
- 获取id在2到6之间的留言信息,并按时间降序排序
- 统计每个作者留了多少条留言,并对数量按从小到大排序。
- 将id为8、9的两条数据的作者改为’doudou’.
- 取出最新的三条留言。
- 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
- 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 ###
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;
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);
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)
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');
查询以下题目:
- 查询学习课程"python"比课程 "java" 成绩高的学生的学号;
- 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);
- 查询所有同学的姓名、选课数、总成绩;
- 查询所有的课程的名称以及对应的任课老师姓名;
- 查询没学过“alex”老师课的同学的姓名;
- 查询学过'python'并且也学过编号'java'课程的同学的姓名;
- 查询学过“alex”老师所教的全部课程的同学的姓名;
- 查询挂科超过两门(包括两门)的学生姓名;
- 查询有课程成绩小于60分的同学的姓名;
- 查询选修了全部课程的学生姓名;
- 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;
- 查询学过'貂蝉'同学全部课程 的其他同学姓名;
- 查询和'貂蝉'同学学习的课程完全相同的,其他同学姓名;
- 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
- 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]
- 查询每门课程被选修的次数
- 查询出只选修了一门课程的学生的学号和姓名
- 查询学生表中男生、女生各有多少人
- 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
- 查询课程名称为“python”,且分数低于60的学生姓名和分数