例子：5.5------5.7.24

1. 下载新的MySQL，本机原有的是MySQL5.5，下载MySQL5.7.24链接https://downloads.mysql.com/archives/community/选择自己要安装的版本（mysql-5.7.24-winx64.zip）
2. 解压，下载完成后解压到自己想要的位置
3. 配置mysql.in,从原有的MySQL5.5的文件夹下复制mysql.ini，粘贴到解压的目录下，
   
4. 修改mysql.ini文件，

# 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]
# 自己想要用哪个端口号就改那个，所有一致
port=3307

[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
# 和上面一致
port=3307


#Path to installation directory. All paths are usually resolved relative to this.
# 解压路径
basedir="G:/MySQL/mysql-5.7.24-winx64/"

#Path to the database root
# 解压路径这里写data，但是目录下不要自己新建
datadir="G:/MySQL/mysql-5.7.24-winx64/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=latin1

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

# Set the SQL mode to strict
sql-mode="STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION"

# 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
max_allowed_packet=500M

wait_timeout=288000 

interactive_timeout = 288000 
character-set-server=utf8
default-storage-engine=INNODB
sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES


# Query cache is used to cache SELECT results and later return them
# without actual executing the same query once again. Having the query
# cache enabled may result in significant speed improvements, if your
# have a lot of identical queries and rarely changing tables. See the
# "Qcache_lowmem_prunes" status variable to check if the current value
# is high enough for your load.
# Note: In case your tables change very often or if your queries are
# textually different every time, the query cache may result in a
# slowdown instead of a performance improvement.
query_cache_size=0
 
# The number of open tables for all threads. Increasing this value
# increases the number of file descriptors that mysqld requires.
# Therefore you have to make sure to set the amount of open files
# allowed to at least 4096 in the variable "open-files-limit" in
# section [mysqld_safe]
table_open_cache=256
 
# Maximum size for internal (in-memory) temporary tables. If a table
# grows larger than this value, it is automatically converted to disk
# based table This limitation is for a single table. There can be many
# of them.
tmp_table_size=35M
 
 
# How many threads we should keep in a cache for reuse. When a client
# disconnects, the client's threads are put in the cache if there aren't
# more than thread_cache_size threads from before.  This greatly reduces
# the amount of thread creations needed if you have a lot of new
# connections. (Normally this doesn't give a notable performance
# improvement if you have a good thread implementation.)
thread_cache_size=8
 
#*** MyISAM Specific options
 
# The maximum size of the temporary file MySQL is allowed to use while
# recreating the index (during REPAIR, ALTER TABLE or LOAD DATA INFILE.
# If the file-size would be bigger than this, the index will be created
# through the key cache (which is slower).
myisam_max_sort_file_size=100G
 
# If the temporary file used for fast index creation would be bigger
# than using the key cache by the amount specified here, then prefer the
# key cache method.  This is mainly used to force long character keys in
# large tables to use the slower key cache method to create the index.
myisam_sort_buffer_size=69M
 
# Size of the Key Buffer, used to cache index blocks for MyISAM tables.
# Do not set it larger than 30% of your available memory, as some memory
# is also required by the OS to cache rows. Even if you're not using
# MyISAM tables, you should still set it to 8-64M as it will also be
# used for internal temporary disk tables.
key_buffer_size=55M
 
# Size of the buffer used for doing full table scans of MyISAM tables.
# Allocated per thread, if a full scan is needed.
read_buffer_size=64K
read_rnd_buffer_size=256K
 
# This buffer is allocated when MySQL needs to rebuild the index in
# REPAIR, OPTIMZE, ALTER table statements as well as in LOAD DATA INFILE
# into an empty table. It is allocated per thread so be careful with
# large settings.
sort_buffer_size=256K

1. 以管理员身份去运行命令行窗口
   
2. 进入mysql5.7的bin目录下
3. 安装mysql服务，指定该mysql服务名为mysql2,并根据my.ini文件进行安装，命令如下：

C:\Windows\system32>G:

G:\>cd G:\MySQL\mysql-5.7.24-winx64\bin

G:\MySQL\mysql-5.7.24-winx64\bin>mysqld install mysql5.7.24 
 
成功安装后会提示：
Service successfully installed.

去服务里面，可查看到此时多了一个mysql5.7.24服务

选中原先自己的MySQL服务，右键停止

8. 初始化数据库，在bin目录下执行如下命令

G:\MySQL\mysql-5.7.24-winx64\bin>mysqld --initialize

初始化成功后，命令行没有任何提示。但在mysql5.7文件夹中已自动生成了data目录

9. 打开注册表，找到HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\mysql2,修改ImagePath参数，更正mysql5.7.24服务相关路径。

G:\MySQL\mysql-5.7.24-winx64\bin\mysqld mysql5.7.24

10. 重置root密码，
    在 bin 目录下输入 cmd管理员运行 mysqld --skip-grant-tables ，跳过权限检查启动 mysql。（此时这个界面没有返回值）再重新打开一个 bin 目录下的 cmd管理员命令行
    输入mysql命令，跳过安全检查，直接进入数据库

update user set password = password('新密码') where user = 'root' and host = 'localhost';

如果报错执行 flush privileges; 命令刷新权限表，再重新重置密码

11. 执行 flush privileges; 命令刷新权限表
12. 退出，成功