1：查询用户
select user,host from mysql.user;
2：删除用户
Delete FROM mysql.user Where User='wordpressusername' and Host='hostname';
3：创建用户
create database testDB;
4：为用户授权和设置密码
GRANT ALL PRIVILEGES ON testDB.* TO "testDB"@"localhost"
IDENTIFIED BY "root";
5：查询在那个用户下
select user();