diff --git "a/24\347\224\230\345\220\257\350\210\252/\346\225\260\346\215\256\345\272\223class3.md" "b/24\347\224\230\345\220\257\350\210\252/\346\225\260\346\215\256\345\272\223class3.md"
new file mode 100644
index 0000000000000000000000000000000000000000..a1af793dae07a8077721f82a799ba232b067b1d7
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+++ "b/24\347\224\230\345\220\257\350\210\252/\346\225\260\346\215\256\345\272\223class3.md"
@@ -0,0 +1,28 @@
+数据库class3
+
+```mysql
+create database class3;
+```
+
+表student字段：学号，姓名，性别，爱好，住址，联系方式，邮箱，QQ号
+并新增一条自己的记录。
+
+```mysql
+use class3;
+create table student(
+id char(10),
+name vachar (5),
+sex vachar (2),
+hobby varchar(10),
+address varchar(100),
+number char(11),
+e-mail char(30),
+qq char (10),
+other varchar (100)    
+ );
+ insert into student(
+   id,name,sex,hobby,address,number,e-mail,qq,other
+ )values(2244310424,甘启航，男，唱跳，安徽，15215559503，gqh20021130@qq.com,2936803841,sybs)
+ ;
+```
+
diff --git "a/24\347\224\230\345\220\257\350\210\252/\347\254\254\344\272\214\344\270\252.md" "b/24\347\224\230\345\220\257\350\210\252/\347\254\254\344\272\214\344\270\252.md"
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+++ "b/24\347\224\230\345\220\257\350\210\252/\347\254\254\344\272\214\344\270\252.md"
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+第二个
+
+```mysql
+create database if not EXISTS test01_market default charset utf8; use test01_market; create table customers( c_num int(11), c_name varchar(50), c_contact varchar(50), c_city varchar(50), c_birth date ); alter table customers MODIFY c_contact varchar(50) after c_birth; alter table customers modify c_name varchar(70); alter table customers change c_contact c_phone; alter table customers add c_gender char(1) after c_name; alter table customers rename to customers_info; alter table customers_info drop c_city;
+
+
+```
+
+
+
+第三个
+
+```mysql
+Create database if not exists test_library default charset utf8;
+Use test_library; 
+Create table books( b_id int(11) comment'书编号',
+b_name varchar(20) comment'书名',
+authors varchar(20) comment'作者',
+price float comment'价值',
+pubdate year comment'发布日期',
+note varchar(20)comment'说明',
+num int(11) comment'库存' );
+insert into books (b_id,b_name,authors,price,pubdate,note,num) 
+values (1,Tal of SSS,Dickes,23,1995,novel,11); insert into books values 
+(2,EmmaT,Jane lura,35,1993,joke,22); 
+insert into books values (3,Story of Jane,Jane Tim,40,2001,nove,10),
+(4,Lovey DayGeorge,Byron,20,2005,novel,30),
+(5,Old land,Honore Blade,30,2010,law,0),
+(7,Rose Hood,Richardhaggard,28,2008,cartoon,28);
+update books set price=price+5 where note=novel;
+update books set price=40 where b_name=EmmaT;
+delete from books where num=0;
+```
+
+第四个
+
+```mysql
+
+Create database if not exists test03_booktore default charset utf8;
+use test03_booktore; 
+create table book
+( id int auto_increment not null primary key,
+ title varchar(100) not null,
+ author varchar(100) not null,
+ price double(11,2) not null,
+ sales int(11) not null,
+ stock int(11) not null,
+ img_path varchar(100) not null );
+ insert into boo;
+```
+