MacMySQLのパスワード変更ができない

Macで新しくMySQL5.7のパスワード変更しようとしてもできない現象発生

Macで新しくMySQL5.7のパスワード変更しようとしてもできない現象発生しました。

MySQLを起動してMySQLに接続

$ mysql.server start
$ mysql -u root

MySQLのパスワードの変更

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

パスワード変更しようとしたらエラーが発生

ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '('root') WHERE user='root'' at line 1

なんと!!MySQL5.7以上はPASSWORD関数が使えないのです

MacMySQLのパスワード変更ができないときの解決方法

スーパーユーザーになってmysql_secure_installationでパスワードを設定します。

$ sudo -s
$ mysql_secure_installation

パスワードの設定画面が出ています。一番はじめにパスワードの強さを聞かれるので一番弱い0(LOW 8文字以上)を選択してパスワードを入力します。あとは全部yで進んでいけばOKです。本当は開発環境なので短いパスワードがよかったのですが設定が面倒なので適当なパスワードを8文字以上入れて使っています。あとはmysql -u root -pでパスワードを使用して入れるかどうか確認できれば解決です!

Securing the MySQL server deployment.
Connecting to MySQL using a blank password.
VALIDATE PASSWORD COMPONENT can be used to test passwords
and improve security. It checks the strength of password
and allows the users to set only those passwords which are
secure enough. Would you like to setup VALIDATE PASSWORD component?
Press y|Y for Yes, any other key for No: y
There are three levels of password validation policy:
LOW    Length >= 8
MEDIUM Length >= 8, numeric, mixed case, and special characters
STRONG Length >= 8, numeric, mixed case, special characters and dictionary                  file
Please enter 0 = LOW, 1 = MEDIUM and 2 = STRONG: 0
Please set the password for root here.
New password: 
Re-enter new password: 
Estimated strength of the password: 50 
Do you wish to continue with the password provided?(Press y|Y for Yes, any other key for No) : y
By default, a MySQL installation has an anonymous user,
allowing anyone to log into MySQL without having to have
a user account created for them. This is intended only for
testing, and to make the installation go a bit smoother.
You should remove them before moving into a production
environment.
Remove anonymous users? (Press y|Y for Yes, any other key for No) : y
Success.
Normally, root should only be allowed to connect from
'localhost'. This ensures that someone cannot guess at
the root password from the network.
Disallow root login remotely? (Press y|Y for Yes, any other key for No) : y
Success.
By default, MySQL comes with a database named 'test' that
anyone can access. This is also intended only for testing,
and should be removed before moving into a production
environment.
Remove test database and access to it? (Press y|Y for Yes, any other key for No) : y
- Dropping test database...
Success.
- Removing privileges on test database...
Success.
Reloading the privilege tables will ensure that all changes
made so far will take effect immediately.
Reload privilege tables now? (Press y|Y for Yes, any other key for No) : y
Success.
All done!