之前安装过一个Mysql5.7版本的，由于项目中使用的是老版本的所以又装了一个5.5的，不同版本的区别还是挺大的。
1.免安装mysql下载地址，msi后缀的是安装包根据引导安装就好，zip的是免安装的需要配置环境变量
https://dev.mysql.com/downloads/mysql/5.5.html#downloads
2.解压到一个位置，复制my-small.ini文件改名为my.ini,初始化服务的时候会重这里面加载配置文件。
比较重要的几个地方就是要修改端口号，因为之前3306已经被用过了，所以我把它改成了3307，还有两个字符设置为utf-8，
还有两个目录根据自己的软件的位置进行配置。一些其他的参数也可以在这里面改。
# Example MySQL config file for small systems.
#
# This is for a system with little memory (<= 64M) where MySQL is only used
# from time to time and it's important that the mysqld daemon
# doesn't use much resources.
#
# MySQL programs look for option files in a set of
# locations which depend on the deployment platform.
# You can copy this option file to one of those
# locations. For information about these locations, see:
# http://dev.mysql.com/doc/mysql/en/option-files.html
#
# In this file, you can use all long options that a program supports.
# If you want to know which options a program supports, run the program
# with the "--help" option.
# The following options will be passed to all MySQL clients
[client]
default-character-set=utf8
#password = your_password
port = 3307
socket = /tmp/mysql.sock
# Here follows entries for some specific programs
# The MySQL server
[mysqld]
basedir = D:/software/mysql-5.5.62-winx64
datadir = D:/software/mysql-5.5.62-winx64/data
character-set-server = utf8
port = 3307
socket = /tmp/mysql.sock
skip-external-locking
key_buffer_size = 16K
max_allowed_packet = 1M
table_open_cache = 4
sort_buffer_size = 64K
read_buffer_size = 256K
read_rnd_buffer_size = 256K
net_buffer_length = 2K
thread_stack = 128K
# Don't listen on a TCP/IP port at all. This can be a security enhancement,
# if all processes that need to connect to mysqld run on the same host.
# All interaction with mysqld must be made via Unix sockets or named pipes.
# Note that using this option without enabling named pipes on Windows
# (using the "enable-named-pipe" option) will render mysqld useless!
#
#skip-networking
server-id = 1
# Uncomment the following if you want to log updates
#log-bin=mysql-bin
# binary logging format - mixed recommended
#binlog_format=mixed
# Causes updates to non-transactional engines using statement format to be
# written directly to binary log. Before using this option make sure that
# there are no dependencies between transactional and non-transactional
# tables such as in the statement INSERT INTO t_myisam SELECT * FROM
# t_innodb; otherwise, slaves may diverge from the master.
#binlog_direct_non_transactional_updates=TRUE
# Uncomment the following if you are using InnoDB tables
#innodb_data_home_dir = C:\\mysql\\data\\
#innodb_data_file_path = ibdata1:10M:autoextend
#innodb_log_group_home_dir = C:\\mysql\\data\\
# You can set .._buffer_pool_size up to 50 - 80 %
# of RAM but beware of setting memory usage too high
#innodb_buffer_pool_size = 16M
#innodb_additional_mem_pool_size = 2M
# Set .._log_file_size to 25 % of buffer pool size
#innodb_log_file_size = 5M
#innodb_log_buffer_size = 8M
#innodb_flush_log_at_trx_commit = 1
#innodb_lock_wait_timeout = 50
[mysqldump]
quick
max_allowed_packet = 16M
[mysql]
no-auto-rehash
# Remove the next comment character if you are not familiar with SQL
#safe-updates
[myisamchk]
key_buffer_size = 8M
sort_buffer_size = 8M
[mysqlhotcopy]
interactive-timeout3.环境变量配置
D:\software\mysql-5.5.62-winx64\bin添加到环境变量
如果你原来的mysql配置了环境变量，需要先去除mysql的环境变量（这个会影响数据库的服务注册，版本就还是会之前的那个）
4.添加服务
cmd进入到bin目录下
这样我们就安装好了，可以在服务里面同时打开两个不同的版本。
