diff --git "a/11 \351\273\216\344\277\212\346\235\250/20230221\347\272\246\346\235\237\344\275\234\344\270\232/zuoye1.sql" "b/11 \351\273\216\344\277\212\346\235\250/20230221\347\272\246\346\235\237\344\275\234\344\270\232/zuoye1.sql"
new file mode 100644
index 0000000000000000000000000000000000000000..bfe4a8948bb80d08edd885a5020d9d76fac6f0ff
--- /dev/null
+++ "b/11 \351\273\216\344\277\212\346\235\250/20230221\347\272\246\346\235\237\344\275\234\344\270\232/zuoye1.sql"	
@@ -0,0 +1,38 @@
+create database test01_company;
+
+use test01_company;
+
+create table offices(
+officeCode int,
+city varchar(30),
+address varchar(50),
+country varchar(50),
+postalCode varchar(25)
+);
+
+create table employees(
+empNum int(11),
+lastName varchar(50),
+firstName varchar(50),
+mobile varchar(25),
+code int,
+jobTitle varchar(50),
+birth date,
+Note varchar(255),
+Sex varchar(5)
+);
+
+alter table employees modify mobile varchar(25) after code;
+
+alter table employees change birth birthday date;
+
+alter table employees modify sex char(1);
+
+alter table employees drop note;
+
+alter table employees add favoriate_activity varchar(100);
+
+alter table employees rename to employees_info
+
+desc employees;
+
diff --git "a/11 \351\273\216\344\277\212\346\235\250/20230221\347\272\246\346\235\237\344\275\234\344\270\232/zuoye2.sql" "b/11 \351\273\216\344\277\212\346\235\250/20230221\347\272\246\346\235\237\344\275\234\344\270\232/zuoye2.sql"
new file mode 100644
index 0000000000000000000000000000000000000000..acef5c33c766441ee13740b60b1b8f30c3c530ab
--- /dev/null
+++ "b/11 \351\273\216\344\277\212\346\235\250/20230221\347\272\246\346\235\237\344\275\234\344\270\232/zuoye2.sql"	
@@ -0,0 +1,42 @@
+create database test02db;
+
+use test02db;
+
+create table pet(
+name varchar(20) comment '宠物名称',
+owner varchar(20) comment '宠物主人',
+species varchar(20) comment '种类',
+sex char(1) comment '性别',
+birth year comment '出生日期',
+death YEAR comment '死亡日期'
+);
+
+insert into pet values('Fluffy','harold','Cat','f',2003,2010);
+
+select * from pet;
+
+insert into pet (name,owner,species,sex,birth) values ('Claws','gwen','Cat','m',2004);
+
+insert into pet (name,species,sex,birth) values ('Buffy','Dog','f',2009);
+
+insert into pet (name,owner,species,sex,birth) values ('Fang','benny','Dog','m',2000);
+
+insert into pet (name,owner,species,sex,birth,death) values('bowser','diane','Dog','m',2003,2009);
+
+insert into pet (name,species,sex,birth) values ('Chirpy','Bird','f',2008);
+
+select * from pet;
+
+alter table pet add owner_birth year comment '主人生日';
+
+update pet set owner='kevin' where name='Claws';
+
+update pet set owner='duck' where death is null and species ='Dog';
+
+select name from pet where isnull(owner)=1;
+
+select name,owner,death from pet where  ISNULL(death)=0 and species='Cat';
+
+delete from pet where ISNULL(death)=0 and species='Dog';
+
+select * from pet;
\ No newline at end of file
diff --git "a/11 \351\273\216\344\277\212\346\235\250/20230221\347\272\246\346\235\237\344\275\234\344\270\232/zuoye3.sql" "b/11 \351\273\216\344\277\212\346\235\250/20230221\347\272\246\346\235\237\344\275\234\344\270\232/zuoye3.sql"
new file mode 100644
index 0000000000000000000000000000000000000000..c47fef153a4674da47d688bebf3902b43a1e3dc8
--- /dev/null
+++ "b/11 \351\273\216\344\277\212\346\235\250/20230221\347\272\246\346\235\237\344\275\234\344\270\232/zuoye3.sql"	
@@ -0,0 +1,48 @@
+create database test03_company charset utf8;
+
+use test03_company ;
+
+create table department(
+	depid int primary key auto_increment,
+    depname char(10) not null unique key,
+    deinfo varchar(200)
+);
+
+create table employee (
+	empid int primary key auto_increment,
+  name varchar(10) not null,
+  sex enum('男','女') not null default '男',
+  title varchar(10),
+  birthday date,
+  depid int,
+	foreign key (depid) references department(depid) 
+);
+
+create table salary(
+empid int	primary key,
+basesalary int,
+titlesalary int,
+deduction int
+);
+
+insert into department (depid,depname) values (111,'生产部');
+
+insert into department (depid,depname) values (222,'销售部');
+
+insert into department (depid,depname,deinfo) values (333,'人事部','人力资源管理');
+
+insert into employee values 
+(1001,'张三','男','高级工程师','1975-1-1',111);
+
+
+insert into employee values 
+(1002,'李四','女','助工','1985-1-1',111),
+(1003,'王五','男','工程师','1978-11-11',222),
+(1004,'张六','男','工程师','1999-1-1',222);
+
+insert into salary values (1001,2200,1100,200);
+
+insert into salary (empid,basesalary,titlesalary) values (1002,1200,200);
+
+insert into salary values (1003,2900,700,200);
+insert into salary values (1004,1950,700,150);
\ No newline at end of file
diff --git "a/11 \351\273\216\344\277\212\346\235\250/20230221\347\272\246\346\235\237\344\275\234\344\270\232/zuoye4.sql" "b/11 \351\273\216\344\277\212\346\235\250/20230221\347\272\246\346\235\237\344\275\234\344\270\232/zuoye4.sql"
new file mode 100644
index 0000000000000000000000000000000000000000..4a2c048681fa44618f22d4cce7f85816e7e3ca36
--- /dev/null
+++ "b/11 \351\273\216\344\277\212\346\235\250/20230221\347\272\246\346\235\237\344\275\234\344\270\232/zuoye4.sql"	
@@ -0,0 +1,37 @@
+create database test04_school charset utf8;
+
+show databases;
+
+use test04_school;
+
+create table Department(
+DepNo int(10) PRIMARY KEY not null comment '部门号',
+DepName varchar(20) not null comment '部门名称',
+DepNote varchar(50)
+);
+
+create table Teacher(
+Number int primary key not null comment '教工号',
+Name varchar(30) not null comment '姓名',
+Sex varchar(4) comment '姓名',
+Birth date comment '出生日期',
+DepNo int comment '部门号',
+Salary float comment '工资',
+Address varchar(100) comment '家庭住址',
+FOREIGN KEY (DepNo) REFERENCES Department(DepNo)
+);
+
+insert into Department values 
+(601,'软件技术系','软件技术等专业'),
+(602,'网络技术系','多媒体技术等专业'),
+(603,'艺术设计系','广告艺术设计等专业'),
+(604,'管理工程系','连锁经营管理等专业');
+
+insert into Teacher VALUES 
+(2001,'Tom','女','1970-01-10',602,4500,'四川省绵阳市'),
+(2002,'Lucy','男','1983-12-18',601,2500,'北京市昌平区'),
+(2003,'Mike','男','1990-06-01',604,1500,'重庆市渝中区'),
+(2004,'James','女','1980-10-20',602,3500,'四川省成都市'),
+(2005,'Jack','男','1975-05-30',603,1200,'重庆市南岸区');
+
+select * from Teacher;
\ No newline at end of file