MySQL下載地址：http://dev.mysql.com/downloads/mysql/
Windows下安裝MySQL
我下的是最新版的MySQL，解壓后，目錄如下：
1.進入dos的命令行，一定要用administrator進入。
2.進入MySQL的bin目錄，輸入mysqld –install可以安裝MySQL
cd D:\idea\mysql-8.0.18-winx64\mysql-8.0.18-winx64\bin
D:
D:\idea\mysql-8.0.18-winx64\mysql-8.0.18-winx64\bin
D:\idea\mysql-8.0.18-winx64\mysql-8.0.18-winx64>mysqld -install
Service successfully installed.
3.輸入以下命令，可以初始化MySQL數據庫，初始化了之后，會打印出MySQL的默認生成的密碼，下面標紅了的就是默認生成的密碼。
D:\idea\mysql-8.0.18-winx64\mysql-8.0.18-winx64>mysqld --initialize --user=root --console
2019-12-20T02:28:44.093039Z 0 [System] [MY-013169] [Server] D:\idea\mysql-8.0.18-winx64\mysql-8.0.18-winx64\bin\mysqld.exe (mysqld 8.0.18) initializing of server in progress as process 7500
2019-12-20T02:28:51.796888Z 5 [Note] [MY-010454] [Server] A temporary password is generated for root@localhost: 4IfH4*eywsg=
初始化了以后，可以看到MySQL目錄下，多了data目錄
4.啟動MySQL服務
D:\idea\mysql-8.0.18-winx64\mysql-8.0.18-winx64>net start mysql
MySQL 服務正在啟動 ..
MySQL 服務已經啟動成功。
5.使用默認生成的密碼，進入mysql
D:\idea\mysql-8.0.18-winx64\mysql-8.0.18-winx64>mysql -u root -p4IfH4*eywsg=
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 11
Server version: 8.0.18
Copyright (c) 2000, 2019, 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>
6.修改密碼
mysql> ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY '123';
Query OK, 0 rows affected (0.01 sec)
7.退出，修改成功