重新查看当前有哪些数据库

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

drop database testdb;

mysql -u root -pleizhimin testdb <C:\testdb.sql