创建新用户

mysql -u root -p//root登录MySQL
password: ******//输入密码

create testname@localhost identified by '123456';//创建新用户testname,密码为123456
create database testdb;//创建数据库testdb
grant all privileges on testdb.* to testname@localhost identified by '123456';//授权给新用户testname
flush privileges;//刷新系统权限表

drop database testdb; //删除用户的数据库
drop user testname@'%';//删除testname用户的权限
drop user testname@localhost;//删除testname用户

用户testname登录

mysql -utestname -p123456 //新用户testname登录
use testdb;//使用 testdb 数据库
//建表等操作