2.在test数据库中创建student表,表结构如下图所示(id设置为主键自增长)
CREATE TABLE student(
sid INT PRIMARY KEY AUTO_INCREMENT,
sname VARCHAR(20),
score INT,
address VARCHAR(50),
useremail VARCHAR(20)
);
//向student表中添加记录如下图所示
INSERT INTO student VALUES(1,'张三',98,'北京','111111111@qq.com'),
(2,'李四',88,'上海','111111112@qq.com'),
(3,'王五',78,'广州','111111113@qq.com'),
(4,'赵六',68,'深圳','111111114@qq.com'),
(5,'孙七',58,'杭州','111111115@qq.com'),
(6,'小红',48,'北京','111111116@qq.com'),
(7,'小黑',99,'上海','111111117@qq.com'),
(8,'小绿',100,'杭州','111111118@qq.com'),
(9,'小粉',60,'杭州','111111119@qq.com'),
(10,'小紫',70,'黑龙江','111111110@qq.com');
//4.使用SQL语句查询出表中的所有内容
SELECT * FROM student
//5.使用SQL语句查询出表中所有同学的id,NAME,score
SELECT sid,sname,score FROM student
//6.更改useremail字段的数据类型为VARCHAR(50)
ALTER TABLE student MODIFY COLUMN useremail VARCHAR(50)
//7.向表中添加一个字段,字段名称为“pingjia”,字段类型为VARCHAR(20)
ALTER TABLE student ADD COLUMN pingjia VARCHAR(20);
//8.更改姓名是张三的同学的分数为88
UPDATE student SET score=88 WHERE sname='张三'
//9.如果80分为及格线,查询出所有及格的同学的详细信息
SELECT *FROM student WHERE score>=80
//10.把姓名是“小红”的同学的分数在原来的基础上+40
UPDATE student SET score=score+40 WHERE sname='小红'
//11.使用关键字IN,查询id值是1或5或7的同学的基本信息
SELECT * FROM student WHERE sid IN(1,5,7);
//12.查询id值在5至8的所有同学的基本信息
SELECT * FROM student sid WHERE sid>=5 AND sid<=8
//13.查询姓名是小红并且分数大于60的同学的基本信息
SELECT * FROM student WHERE sname='小红' AND score>60
//14.查询姓名是小红或者分数大于90的同学的基本信息
SELECT * FROM student WHERE sname='小红' OR score>90
//15.查询score字段值是NULL的同学的基本信息
SELECT * FROM student WHERE score='NULL'
//16.查询score字段值不是NULL的同学的id和NAME
SELECT sid,sname FROM student WHERE score IS NOT NULL
1.创建db_test数据库(10分)
CREATE DATABASE db_test
1.选择db_test数据库(5分)
USE db_tsst
在test数据库中创建yuangong表,表中添加如下记录,表结构参考下方
CREATE TABLE yuangong(
sid INT(10) PRIMARY KEY AUTO_INCREMENT,
sname VARCHAR(50),
sex ENUM('男','女') NOT NULL DEFAULT'男',
job VARCHAR(50),
birthday DATE,
salary INT,
come INT,
withhold INT
);
INSERT INTO yuangong VALUES(1001,'张三','男','高级工程师','1975-1-1',2200,1100,200),
(1002,'李四','女','助工','1985-1-1',1200,1100,100),
(1003,'王五','男','工程师','1978-11-11',1900,110,200),
(1004,'赵六','男','工程师','1979-1-1',19600,1100,150);
2.修改表名为”emp”(10分)
ALTER TABLE yuangong RENAME TO emp;
向表中添加字段Hobby,设置类型为VARCHAR(50),设置唯一约束
ALTER TABLE emp ADD hobby VARCHAR(50)UNIQUE
4.使用DESC语句查看表结构(5分)
DESC emp
向表中添加记录,字段对应值分别为(1005,林青霞,女,架构师,1969-12-12,8000,NULL,100,阅读)(5分)
INSERT INTO emp VALUES(1005,'林青霞','女','架构师','1969-12-12',8000,NULL,100,'阅读')
6.修改sname字段的类型为VARCHAR(20)(5分)
ALTER TABLE emp MODIFY sname VARCHAR(20)
7.查询表中sid字段的值从是1002或1003或1005员工的所有记录(使用关键字IN)(5分)
SELECT * FROM emp WHERE sid IN(1002,1003,1005);
8.修改表中job值是高级工程师员工的job为“架构师”(5分)
UPDATE emp SET job='构架师'WHERE job LIKE'高级工程师'
9.删除表中sid是1003并且job是王五的员工的记录(10分)
DELETE FROM emp WHERE sid=1003 AND sname='王五'
10.修改表中姓名是1004员工的salary在原来的基础上-300(10分)
UPDATE emp SET salary=salary-300 WHERE (sid=1004)
创建一个学校数据库(jiyun)
CREATE DATABASE jiyun CHARACTER SET utf8 COLLATE utf8_general_ci
创建课程(lesson)
CREATE TABLE lesson(
id INT PRIMARY KEY AUTO_INCREMENT,
NAME VARCHAR(10)
)
创建一个班级(cls),包含字段
CREATE TABLE cls(
`id` INT PRIMARY KEY AUTO_INCREMENT,
`name` VARCHAR(20),
`number` INT,
`lesson_id` INT
在lesson表中插入两数据
INSERT INTO lesson (NAME) VALUES ('python高级'),('数据库vue')
1、'python高级'
2、'数据库vue'
在班级表中插入6条记录,
INSERT INTO cls(NAME,number,lesson_id)
VALUES('1905A',22,1),
('1905A',44,1),
('1905A',33,1),
('1905A',18,2),
('1905A',48,2),
('1905A',56,2)
查询类型为 'python高级' 的所有班级、人员数量
SELECT * FROM cls WHERE lesson_id IN(SELECT id FROM lesson WHERE NAME='python高级')
查询每个班级中 人数最多、最少
SELECT MAX(number) AS '人数最多',MIN(number) AS'人数最少' FROM cls
查询所有人员数量大于平均人数的班级,并且按班级人数降序排序
SELECT * FROM cls WHERE number < (SELECT AVG(number) FROM cls) ORDER BY number DESC
修改cls表中'1902A'班级数量为44
UPDATE cls SET number='44' WHERE NAME='1902A'
1.创建库
create database databook
2 自定义类Book
use databook
create table book(
id INT PRIMARY KEY auto_increment,
bookname VARCHAR(30),
price int,
author VARCHAR(30),
publish VARCHAR(30)
)
/*
2)向表里添加10条数据
*/
INSERT INTO book(bookname,price,author,publish) VALUES
('北平无故事',25,'刘和平','作家出版社'),
('人间失格',16,'太宰治著','作家出版社'),
('高兴',14,'贾平凹','人民出版社'),
('源氏物语',57,'刘和平','人民出版社'),
('卡夫卡文集',9,'卡夫卡','邮电出版社'),
('大家',12,'王蒙','邮电出版社'),
('拉片子',37,'杨健','清华出版社'),
('古代散文',5,'归有光','安徽出版社'),
('百花散文',6,'孙虹选','百花文艺出版社'),
('方令孺散文集',5,'方令孺','安徽文艺')
3查询所有图书的信息,并按价格降序显示
SELECT * FROM book where price order by price asc
4)查询所有作家出版社的图书信息,并按价格降序显示
SELECT author FROM book where price order by price desc
5查询出所有刘和平的图书信息 ,并输出
SELECT * FROM book where author = '刘和平'
6)删除ID是2的记录,如果没有相关记录则提示
DELETE from book where id = 2
SELECT * from book
7)将所有价格不足10元的图书调到10元,并查看信息
UPDATE book set price = 10 where price <10
8查看所有图书的价格情况,并升序显示
SELECT price from book where price order by price asc
9查看所有价格低于20元的图收信息
select publish from book where price <=20