無法連線的原因是mysql8與mysql5的加密方式不同。

連線時會出現1251錯誤。

解決辦法：

1.先通過命令列進入mysql的root賬戶：

PS C:\Windows\system32> mysql -uroot -p

再輸入root的密碼：

Enter password: ******
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 18
Server version: 8.0.11 MySQL Community Server - GPL
Copyright (c) 2000, 2018, 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.
mysql>
 

2.更改加密方式：

mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'password' PASSWORD EXPIRE NEVER;
Query OK, 0 rows affected (0.10 sec)

3.更改密碼：

mysql> ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'password';
Query OK, 0 rows affected (0.35 sec)

4.重新整理：

mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.28 sec)
 

// 如果報錯 ERROR 1396 (HY000): Operation ALTER USER failed for 'root'@'%' ：

則是遠端訪問許可權不正確，先選擇資料庫，檢視一下再更改：

mysql> use mysql;
Database changed

mysql> select user,host from user;
+------------------+-----------+
| user             | host      |
+------------------+-----------+
| mysql.infoschema | localhost |
| mysql.session    | localhost |
| mysql.sys        | localhost |
| root             | localhost |
+------------------+-----------+
5 rows in set (0.00 sec)