现在brew install mysql已经默认成了安装MySQL 8，而MySQL 8和MySQL 5不兼容所以怎样在最新的homebrew下安装MySQL 5.7呢，找到了这个文章，写的很好：https://medium.com/@at0dd/install-mysql-5-7-on-mac-os-mojave-cd07ec936034

# 来自https://medium.com/@at0dd/install-mysql-5-7-on-mac-os-mojave-cd07ec936034

# 如果已经安装了MySQL 8，先进行卸载
brew uninstall mysql
brew uninstall mysql@5.7
rm -rf /usr/local/var/mysql
rm /usr/local/etc/my.cnf

# 安装MySQL 5.7
brew install mysql@5.7
# 强行link
brew link --force mysql@5.7
# 注册并启动服务
brew services start mysql@5.7
# 重置密码
mysql_secure_installation