您可以使用:

SET PASSWORD FOR 'root' = PASSWORD('elephant7');

或者，最新版本:

SET PASSWORD FOR root = 'elephant7' 

您还可以使用:

UPDATE user SET password=password('elephant7') WHERE user='root';

但是在Mysql 5.7中，字段密码不再存在，您必须使用:

but in Mysql 5.7 the field password is no more there, and you have to use:

UPDATE user SET authentication_string=password('elephant7') WHERE user='root';

致谢