use xuexiao;

create table studentInfo (
    `name` varchar(10),
    sex char,
    age int,
    address varchar(20)
    
);

show tables;
-- 插入操作
-- 值需要按照字段的顺序一一对应 ，如果插入的值顺序和创建表顺序相同，则字段可以省略
insert into studentInfo(`name` , sex , age , address ) values ("张三" ,'男',19,'河南省许昌市');
insert into studentInfo(sex , address , age , name ) values ("女" ,'河南省郑州市',29,'小红');
insert into studentInfo values ("小黑" ,'男',39,'河南省沧州市');
select * from studentInfo;

-- 修改已创建的表字段默认值
alter table studentInfo change sex sex char default '男';

insert into studentInfo(`name` , sex , age , address ) values ("翠花" ,'女',18,'河南省许昌市');
insert into studentInfo(sex , address , age , name ) values ("女" ,'河南省郑州市',49,'秀莲');
insert into studentInfo values ( "黑斯", '男',29,'河北省邯郸市');  -- 有默认值 如果省略字段，则值需要写全
select * from studentInfo;

create table studentInfo2 (
    id int auto_increment primary key,
    `name` varchar(10),
    sex char,
    age int,
    address varchar(20)
    
);

show tables;
insert into studentInfo2(id , `name` , sex , age , address ) values (1 ,"翠花" ,'女',18,'河南省许昌市');
insert into studentInfo2(`name` , sex , age , address ) values ("翠花" ,'女',18,'河南省许昌市');
insert into studentInfo2(id , `name` , sex , age , address ) values (3 ,"翠花2" ,'女',18,'河南省许昌市');
insert into studentInfo2(id , `name` , sex , age , address ) values (2 ,"翠花2" ,'女',18,'河南省许昌市');
insert into studentInfo2(`name` , sex , age , address )  values ( "黑斯", '男',29,'河北省邯郸市'),
 ( "李逵", '男',29,'河北省邯郸市'),
 ( "宋江", '男',29,'河北省邯郸市'),
 ( "吴用", '男',29,'河北省邯郸市'),
 ( "公孙胜", '男',29,'河北省邯郸市');
 desc studentInfo2;
 select * from studentInfo2;
 select * from studentInfo;
 insert into studentInfo values ( "黑斯", '男',29,'河北省邯郸市'),
 ( "李逵", '男',29,'河北省邯郸市'),
 ( "宋江", '男',29,'河北省邯郸市'),
 ( "吴用", '男',29,'河北省邯郸市'),
 ( "公孙胜", '男',29,'河北省邯郸市');
 
 
  insert into studentInfo2 values ( 11,"黑斯", '男',29,'河北省邯郸市'),
 ( 12,"李逵", '男',29,'河北省邯郸市'),
 ( 13,"宋江", '男',29,'河北省邯郸市'),
 ( 14,"吴用", '男',29,'河北省邯郸市'),
 ( 15,"公孙胜", '男',29,'河北省邯郸市');
 
select * from studentInfo2;

-- 修改  update ... set ... where 条件
-- 修改指定的数据
update studentInfo set name="潘金莲" where name ="秀莲";
-- 没有写条件，则修改全部的数据
update studentInfo set name ="潘金莲" ;

-- 删除 delete from table where ...  有日志留下，可以恢复
delete from studentInfo2 where name="翠花2"; -- 删除符合条件的数据
delete from studentinfo;  -- 删除所有数据


-- 销毁数据 布留下日志，速度快，无法恢复
truncate table studentInfo2;