mysql数据的增删改案例

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mysql数据的增删改案例

直接po截图和代码

#mysql数据的增删改案例
USE myemployees;
#1.运行以下脚本创建表my_employees
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

);

#2.显示表my_employees的结构
DESC my_employees;

#3.向my_employees表中插入下列数据
/*
ID	FIRST_NAME	LAST_NAME	USERID	SALARY
1	patel		Ralph		Rpatel	895
2	Dancs		Betty		Bdancs	860
3	Biri		Ben		Bbiri	1100
4	Newman		Chad		Cnewman	750
5	Ropeburn	Audrey		Aropebur 1550
*/

#方式一
INSERT INTO my_employees(id, FIRST_NAME, LAST_NAME, USERID, SALARY)
VALUES(1, 'patel', 'Ralph', 'Rpatel', 895),
(2, 'Dancs', 'Betty', 'Bdancs', 860),
(3, 'Biri', 'Ben', 'Bbiri', 1100),
(4, 'Newman', 'Chad', 'Cnewman', 750),
(5, 'Ropeburn', 'Audrey', 'Aropebur', 1550);
#
SELECT * FROM my_employees;
#
DELETE FROM my_employees;
#表名后面省略字段
INSERT INTO my_employees
VALUES(1, 'patel', 'Ralph', 'Rpatel', 895),
(2, 'Dancs', 'Betty', 'Bdancs', 860),
(3, 'Biri', 'Ben', 'Bbiri', 1100),
(4, 'Newman', 'Chad', 'Cnewman', 750),
(5, 'Ropeburn', 'Audrey', 'Aropebur', 1550);
#方式二(用到了子查询和UNION联合查询)
INSERT INTO my_employees
SELECT 1, 'patel', 'Ralph', 'Rpatel', 895 UNION
SELECT 2, 'Dancs', 'Betty', 'Bdancs', 860 UNION
SELECT 3, 'Biri', 'Ben', 'Bbiri', 1100 UNION
SELECT 4, 'Newman', 'Chad', 'Cnewman', 750 UNION
SELECT 5, 'Ropeburn', 'Audrey', 'Aropebur', 1550;

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


#5.将3号员工的last_name修改为“drelxer”
UPDATE my_employees SET Last_name = 'drelxer' WHERE id = 3;

#6.将所有工资少于900的员工的工资修改为1000
UPDATE my_employees SET Salary = 1000 WHERE Salary < 900;

#7.将userid 为Bbiri的user表和my_employees表的记录全部删除
#级联删除/修改多表
DELETE u, m FROM users u INNER JOIN my_employees m
ON u.userid = m.`Userid`
WHERE u.`Userid` = 'Bbiri';

#8.删除所有数据
DELETE FROM my_employees;
DELETE FROM users;

#9.检查所作的修正
SELECT * FROM my_employees;
SELECT * FROM users;

#10.清空表my_employees
TRUNCATE TABLE my_employees;