• 查看是否有mysql57安装包

$ brew search mysql
==> Formulae
automysqlbackup          mysql++                  mysql-cluster            mysql-connector-c++      mysql-search-replace     mysql@5.5                mysql@5.7
mysql                    mysql-client             mysql-connector-c        mysql-sandbox            mysql-utilities          mysql@5.6                mysqltuner

==> Casks
mysql-connector-python        mysql-shell                   mysql-utilities               mysqlworkbench                navicat-for-mysql             sqlpro-for-mysql

• 安装mysql57

$ brew install mysql@5.7
Updating Homebrew...
==> Auto-updated Homebrew!
Updated 1 tap (homebrew/cask-fonts).
No changes to formulae.

==> Downloading https://mirrors.ustc.edu.cn/homebrew-bottles/bottles/mysql@5.7-5.7.25.mojave.bottle.tar.gz
######################################################################## 100.0%
==> Pouring mysql@5.7-5.7.25.mojave.bottle.tar.gz
==> Caveats
We've installed your MySQL database without a root password. To secure it run:
    mysql_secure_installation

MySQL is configured to only allow connections from localhost by default

To connect run:
    mysql -uroot

mysql@5.7 is keg-only, which means it was not symlinked into /usr/local,
because this is an alternate version of another formula.

If you need to have mysql@5.7 first in your PATH run:
  echo 'export PATH="/usr/local/opt/mysql@5.7/bin:$PATH"' >> ~/.zshrc

For compilers to find mysql@5.7 you may need to set:
  export LDFLAGS="-L/usr/local/opt/mysql@5.7/lib"
  export CPPFLAGS="-I/usr/local/opt/mysql@5.7/include"

For pkg-config to find mysql@5.7 you may need to set:
  export PKG_CONFIG_PATH="/usr/local/opt/mysql@5.7/lib/pkgconfig"


To have launchd start mysql@5.7 now and restart at login:
  brew services start mysql@5.7
Or, if you don't want/need a background service you can just run:
  /usr/local/opt/mysql@5.7/bin/mysql.server start
==> Summary
/usr/local/Cellar/mysql@5.7/5.7.25: 319 files, 234MB

• 安装后按照上面命令添加全局变量
• 但是mysql还是死活都启动不起来

$ mysql.server restart
 ERROR! MySQL server PID file could not be found!
Starting MySQL
. ERROR! The server quit without updating PID file (/usr/local/var/mysql_bak/K-MacBook-Pro.local.pid).

• 只能将原来的目录进行备份，删除 /usr/local/var/mysql 目录，执行 mysqld --initialize 重新初始化一个mysql目录，启动成功
• 但是之前的数据库数据就都没了，后面尝试将新初始化目录中的pid文件复制到旧的备份mysql文件中去，并且设置下 my.conf 文件中的 datadir 的指向配置

  1 # Default Homebrew MySQL server config
  2 [mysqld]
  3 # Only allow connections from localhost
  4 bind-address = 127.0.0.1
  5
  6 datadir      = /usr/local/var/mysql/

重新启动成功，并且数据库都回来了