ターミナル

## MySQLに root で接続
$ mysql -uroot -p

## ユーザー作成
> CREATE USER 'homestead'@'localhost' IDENTIFIED BY 'XXX';

## ユーザーに全権限追加
> GRANT ALL ON *.* TO 'homestead'@'localhost' IDENTIFIED BY 'XXX';
>> エラー発生

## 権限の変更をデータベースに反映
FLUSH PRIVILEGES;

GRANT でエラー発生
原因：MySQL8.0ではGRANT構文でユーザを作成できない
↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓
解決策

ターミナル

## MySQLに root で接続
$ mysql -uroot -p

## ユーザー作成
> CREATE USER 'homestead'@'localhost' IDENTIFIED BY 'XXX';

## ユーザーに全権限追加
> GRANT all ON *.* TO 'homestead'@'localhost';

## 権限の変更をデータベースに反映
> FLUSH PRIVILEGES;

log

## MySQLに root で接続
$ mysql -uroot -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 19
Server version: 8.0.19 Homebrew

Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

## ユーザー作成
mysql>
mysql> CREATE USER 'homestead'@'localhost' IDENTIFIED BY 'XXX';
Query OK, 0 rows affected (0.00 sec)

## ユーザーに権限追加
mysql> GRANT ALL ON *.* TO 'homestead'@'localhost' IDENTIFIED BY 'XXX';
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 'IDENTIFIED BY 'XXX'' at line 1
>> エラー発生

参考記事：https://www7390uo.sakura.ne.jp/wordpress/archives/456