一、删除原来的MySQL

• 删除 C:\Programs Files、C:\Programs Files(x86)、C:\ProgramData 中的所有MySQL目录

  • 找到MySQL数据库中的data保存到其他位置，升级后可以恢复数据库数据 【备份数据】

• 删除注册表中MySQL的信息

  • 计算机\HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\EventLog\Application下的MySQL

• 删除服务中的MySQL

  • 以管理员的方式启动 cmd， 执行 sc delete MySQL80 或 sc delete MySQL 这个根据自己MySQL的服务名视情况而定

二、下载安装MySQL

• 点击跳转官网下载
• 选择 Custom,正常的都下一步默认，设置密码别忘了，选择安装的时候我除了最后两个都安装了

三、配置

• 默认安装在 C:\Programs Files, 去这个文件夹找 MySQL 然后找 MySQL Server 8.0

• 打开环境变量，在系统变量中修改 MYSQL_HOME 或者添加，内容为 C:\Program Files\MySQL\MySQL Server 8.0\bin【安装目录】

• 这个C:\Program Files\MySQL\MySQL Server 8.0目录下有个 my.ini 文件,如果没有就新建一个

  # For advice on how to change settings please see
  # http://dev.mysql.com/doc/refman/5.6/en/server-configuration-defaults.html
  # *** DO NOT EDIT THIS FILE. It's a template which will be copied to the
  # *** default location during install, and will be replaced if you
  # *** upgrade to a newer version of MySQL.
  [client]
  default-character-set = utf8mb4
  [mysql]
  default-character-set = utf8mb4
  [mysqld]
  character-set-client-handshake = FALSE
  character-set-server = utf8mb4
  collation-server = utf8mb4_bin
  init_connect='SET NAMES utf8mb4'
  # Remove leading # and set to the amount of RAM for the most important data
  # cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.
  innodb_buffer_pool_size = 128M
  # Remove leading # to turn on a very important data integrity option: logging
  # changes to the binary log between backups.
  # log_bin
  # These are commonly set, remove the # and set as required.
  # 下面这俩是工作目录和数据存储目录，自己视情况而定
  basedir = D:\MySQL
  datadir = D:\MySQL\data
  port = 3306
  # server_id = .....
  # Remove leading # to set options mainly useful for reporting servers.
  # The server defaults are faster for transactions and fast SELECTs.
  # Adjust sizes as needed, experiment to find the optimal values.
  join_buffer_size = 128M
  sort_buffer_size = 16M
  read_rnd_buffer_size = 16M 
  sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES
  

• 然后打开 dos 控制台，输入 mysqld --defaults-file="C:\Program Files\MySQL\MySQL Server 8.0\my.ini" 【创建MySQL服务】

之后就可以正常使用我们的 MySQL 了

# 查看版本
mysql --version
# 登录mysql
mysql -u root -p
# 然后输入你的密码

如果使用Navicat 连接 MySQL 出现报错

• 那么可以在dos中登录mysql
• 然后执行 ALTER USER root@localhost IDENTIFIED WITH mysql_native_password BY '你想用的mysql登录密码'; 【修改加密方式】