현재 사용 가능한 데이터베이스를 다시 확인하세요.

show databases

show tables;

use mysql;
grant all on *.* to root@'%' identified by '123' with grant option;
commit;

grant all on *.* to xing@'localhost' identified by '123456' with grant option;
update user set password = password('newpwd') where user = 'xing' and host='localhost';
flush privileges;

create database testdb;

create database if not testdb;

use testdb;
create table table1(
username varchar(12),
password varchar(20));

create table if not exists aaa(ss varchar(20));

describe table1;

insert into table1(username,password) values
('leizhimin','lavasoft'),
('hellokitty','hahhahah');
commit;

select * from table1;

update table1 set password='hehe' where username='hellokitty';
commit;

delete from table1 where username='hellokitty';
commit;

alter table table1 add column(
 sex varchar(2) comment '性别',
 age date not null comment '年龄'
);
commit;

create table tmp as
select * from table1;

drop table if exists table1;
drop table if exists tmp;

mysqldump -h 192.168.3.143 -u root -p pwd -x --default-character-set=gbk >C:\testdb.sql