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MySQL基础增删改查练习

2022-06-09 08:50:00 【Maximize+】

练习1

#增删改查练习
#创建数据库dbtest11
CREATE DATABASE IF NOT EXISTS dbtest11 CHARACTER SET 'utf8'

#以下脚本创建表my_employees
USE dbtest11;
CREATE TABLE my_employees(
		id INT(10),
		first_name VARCHAR(10),
		last_name VARCHAR(10),
		userid VARCHAR(10),
		salary DOUBLE(10,2)
);
CREATE TABLE users(
		id INT,
		userid VARCHAR(10),
		department_id INT
);
SHOW TABLES;

#显示表my_employess的结构
DESC my_employees;
DESC users;

#向my_employees插入数据
INSERT INTO  my_employees
VALUES(1,'patel','Ralph','Rpatel',895);
SELECT*FROM my_employees;

INSERT INTO  my_employees
VALUES
(2,'Dancs','Betty','Bdancs',860),
(3,'Biri','Ben','Bbiri',1100),
(4,'Newman','Chad','Cnewman',750),
(5,'Ropeburn','Audrey','Aropebur',1550);
SELECT*FROM my_employees;


#向users表中插入数据
INSERT INTO users VALUES
(1,'Rpatel',10),
(2,'Bdancs',10),
(3,'Bbiri',20),
(4,'Cnewman',30),
(5,'Aropebur',40);

SELECT*FROM users;

#将3号员工的last_name修改为"drelxer"
UPDATE my_employees
SET last_name = 'drelxer'
WHERE id = 3;

#将所有工资小于900的员工的工资修改为1000
UPDATE my_employees
SET salary = 1000
WHERE salary <900;

#将userid为Bbiri的users表和my_employees表的记录全部删除
#方式1
DELETE FROM my_employees
WHERE userid = 'Bbiri';
DELETE FROM users
WHERE userid = 'Bbiri'; 
#方式2
DELETE m,u
FROM my_employees m 
JOIN users u
ON m.userid = u.userid
WHERE m.userid = 'Bbiri';
SELECT*FROM my_employees;
SELECT*FROM users;

#删除my_employees、users表所有数据
DELETE FROM my_employees;
DELETE FROM users;
#检查修正结果
SELECT*FROM my_employees;
SELECT*FROM users;

#清空my_employees
TRUNCATE TABLE my_employees;
#此时数据无法回滚

练习2

#使用现有的dbtest11数据库
USE dbtest11;

#创建表格pet
CREATE TABLE pet(
	NAME VARCHAR(20),
	OWNER VARCHAR(20),
	species VARCHAR(20),
	sex CHAR(1),
	birth YEAR,
	death YEAR
);

DESC pet;

#添加记录
INSERT INTO pet
VALUES
('Fluffy','harold','Cat','f','2003','2010'),
('Claws','gwen','Cat','m','2004',NULL),
('Buffy',NULL,'Dog','f','2009',NULL),
('Fang','beeny','Dog','m','2000',NULL),
('bowser','diane','Dog','m','2003','2009'),
('Chirpy',NULL,'Bird','f','2008',NULL);

SELECT*FROM pet;

#添加字段：主人的生日owner_birth DATE类型
ALTER TABLE pet
ADD owner_birth DATE;

#将名称为Claws的猫的主人改为Kevin
UPDATE pet
SET OWNER = 'Kevin'
WHERE NAME = 'Claws'; AND species = 'Cat'
SELECT*FROM pet;
#将没有死的狗的主人改为duck
UPDATE pet
SET OWNER = 'duck'
WHERE death IS NULL AND species = 'Dog';
SELECT*FROM pet;

#查询没有主人的宠物名字
SELECT NAME
FROM pet
WHERE OWNER IS NULL;
#查询已经死了的Cat的姓名，主人，以及去世的时间
SELECT NAME,OWNER,death
FROM pet
WHERE death IS NOT NULL AND species = 'Cat';

#删除已经死了的狗
DELETE FROM pet
WHERE death IS NOT NULL
AND species = 'Dog';
SELECT*FROM pet;
#查询所有宠物的信息
SELECT*FROM pet;

练习3

#使用已有的dbtest11
USE dbtest11;

#创建employee,并添加记录
CREATE TABLE employee(
	id INT,
	NAME VARCHAR(15),
	sex CHAR(1),
	tel VARCHAR(25),
	addr VARCHAR(35),
	salary DOUBLE(10,2)
);

INSERT INTO employee(id,NAME,sex,tel,addr,salary)VALUES
(10001,'张一一','男','13456789000','山东青岛',1001.58),
(10002,'刘小红','女','13454319000','河北保定',1201.21),
(10003,'李四','男','0751-1234567','广东佛山',1004.11),
(10004,'刘小强','男','0755-5555555','广东深圳',1501.23),
(10005,'王艳','男','020-1232133','广东广州',1405.16);

SELECT * FROM employee;

#查询出薪资在1200~1300之间的员工信息
SELECT*FROM employee
WHERE salary BETWEEN 1200 AND 1300;
#查询出姓"刘"的员工的工号，姓名，家庭住址
SELECT id,NAME,addr
FROM employee
WHERE NAME LIKE '刘%';

#将李四的家庭住址改为广东韶关

UPDATE employee
SET addr = '广东韶关'
WHERE NAME = '李四';

#查询出名字中带“小”的员工
SELECT *
FROM employee
WHERE NAME LIKE '%小%';