mysql中怎样切换用户登录

SET PASSWORD FOR 'newuser'@'localhost' = PASSWORD('newpassword');

mysql -u newuser -p

USE mysql;
UPDATE user SET Password=PASSWORD('newpassword') WHERE User='newuser';
FLUSH PRIVILEGES;

mysql -u newuser -p

mysql_config_editor set --login-path=client --host=localhost --user=newuser --password
Enter password: 

mysql --login-path=client

mysqladmin -u currentuser -p password 'newpassword' -h localhost

mysql -u newuser -p

CREATE USER 'newuser'@'localhost' IDENTIFIED BY 'newpassword';
GRANT ALL PRIVILEGES ON *.* TO 'newuser'@'localhost';
FLUSH PRIVILEGES;

mysql -u newuser -p

ERROR 1045 (28000): Access denied for user 'newuser'@'localhost' (using password: YES)

CREATE USER 'newuser'@'localhost' IDENTIFIED BY 'newpassword';
FLUSH PRIVILEGES;

ERROR 1044 (42000): Access denied for user 'newuser'@'localhost' to database 'yourdb'

GRANT ALL PRIVILEGES ON yourdb.* TO 'newuser'@'localhost';
FLUSH PRIVILEGES;

ERROR 1045 (28000): Access denied for user 'newuser'@'localhost' (using password: YES)

mysql -u newuser -p