下载的官方压缩包，压缩包里面没有my.ini

拷贝的原来的5.5的，

把Myisam的参数去掉了，剩下以下这些：

# MySQL Server Instance Configuration File

# ----------------------------------------------------------------------

# Generated by the MySQL Server Instance Configuration Wizard

#

#

# Installation Instructions

# ----------------------------------------------------------------------

#

# On Linux you can copy this file to /etc/my.cnf to set global options,

# mysql-data-dir/my.cnf to set server-specific options

# (@localstatedir@ for this installation) or to

# ~/.my.cnf to set user-specific options.

#

# On Windows you should keep this file in the installation directory 

# of your server (e.g. C:\Program Files\MySQL\MySQL Server X.Y). To

# make sure the server reads the config file use the startup option 

# "--defaults-file". 

#

# To run run the server from the command line, execute this in a 

# command line shell, e.g.

# mysqld --defaults-file="C:\Program Files\MySQL\MySQL Server X.Y\my.ini"

#

# To install the server as a Windows service manually, execute this in a 

# command line shell, e.g.

# mysqld --install MySQLXY --defaults-file="C:\Program Files\MySQL\MySQL Server X.Y\my.ini"

#

# And then execute this in a command line shell to start the server, e.g.

# net start MySQLXY

#

#

# Guildlines for editing this file

# ----------------------------------------------------------------------

#

# In this file, you can use all long options that the program supports.

# If you want to know the options a program supports, start the program

# with the "--help" option.

#

# More detailed information about the individual options can also be

# found in the manual.

#

#

# CLIENT SECTION

# ----------------------------------------------------------------------

#

# The following options will be read by MySQL client applications.

# Note that only client applications shipped by MySQL are guaranteed

# to read this section. If you want your own MySQL client program to

# honor these values, you need to specify it as an option during the

# MySQL client library initialization.

#

[client]



port=3306



[mysql]



default-character-set=utf8





# SERVER SECTION

# ----------------------------------------------------------------------

#

# The following options will be read by the MySQL Server. Make sure that

# you have installed the server correctly (see above) so it reads this 

# file.

#

[mysqld]



# The TCP/IP Port the MySQL Server will listen on

port=3306



#定义时区

default-time-zone='+08:00'



#Path to installation directory. All paths are usually resolved relative to this.

basedir="E:/webhome/mysql-8.0.19"



#Path to the database root

#datadir="C:/Documents and Settings/All Users/Application Data/MySQL/MySQL Server 5.5/Data/"

datadir="E:/webhome/mysql-8.0.19/data"



# The default character set that will be used when a new schema or table is

# created and no character set is defined

character-set-server=utf8



# The default storage engine that will be used when create new tables when

default-storage-engine=INNODB



# The maximum amount of concurrent sessions the MySQL server will

# allow. One of these connections will be reserved for a user with

# SUPER privileges to allow the administrator to login even if the

# connection limit has been reached.

max_connections=100





# 默认使用“mysql_native_password”插件认证

default_authentication_plugin=mysql_native_password

最后一句是加上去的，原来5.5的配置里面没有。

下一步：

输入命令，需要是在管理员模式下，并且切换到bin目录：

mysqld –initialize

执行后，如果没有任何输出，也不报错，可能是因为你没有创建data目录，手动创建一个。

再次执行，会在data目录下生成文件。生成文件很多，如果只有两个文件，那就是遇到错误了。

直接打开data目录下，你的主机名.err的文件，里面有错误描述。

特别注意，再次执行上面命令时，需要删除掉data目录下的文件。

执行后，如果卡顿一段时间，并在data目录下生成文件夹及很多文件，表示成功。这个时候可以执行：

mysqld install

注册服务，注册成功后，用net start mysql启动服务。

启动后，root密码在data目录下，刚才看错误的那个文件中

[Note] [MY-010454] [Server] A temporary password is generated for root@localhost: <o15=l1rTD9l

找到这个密码，在命令提示行下登录mysql。

到这里还没完。你登录后，使用Use命令时，会提示：

ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement.

然后就需要执行命令：

[#zeyu#]

alter user user() identified by "你要设置的新密码";

[/#zeyu#]

这样，就可以使用新密码了。但是如果像我是从5.5升级的，而且还有很多表是MyIsAM的话，就比较麻烦了。目前还未处理。