升级到Catalina OS后遇到类似的问题。运行mysqld命令后，我发现日志文件有一些问题。对其他人来说可能不一样。

$ mysqld

问题是

2019-10-16T04:58:59.174474Z 0 [ERROR] Could not open file '/var/log/mysql/error.log' for error logging: No such file or directory
2019-10-16T04:58:59.174508Z 0 [ERROR] Aborting

通过创建它并应用适当的权限来解决它。

sudo mkdir -p /var/log/mysql
sudo touch /var/log/mysql/error.log
sudo chown -R _mysql:mysql /var/log/mysql/

重新启动MySQL

brew services restart mysql@5.7

问题解决了。

mysql -uroot -proot

解决方案围绕:

修改MySQL的权限 sudo chown -R _mysql:mysql /usr/local/var/mysql 启动MySQL进程 sudo mysql。服务器启动

如果上面的命令不能帮你解决这个问题，那就试着指定主机

mysql -u root -p h127.0.0.1

下面我包括了最新的说明从brew安装mysql，以便更新搜索这个问题可以受益:

$ brew install mysql
==> Downloading https://homebrew.bintray.com/bottles/mysql-5.6.26.yosemite.bottle.1.tar.gz
######################################################################## 100.0%
==> Pouring mysql-5.6.26.yosemite.bottle.1.tar.gz

To connect:
    mysql -uroot

To have launchd start mysql at login:
  ln -sfv /usr/local/opt/mysql/*.plist ~/Library/LaunchAgents
Then to load mysql now:
  launchctl load ~/Library/LaunchAgents/homebrew.mxcl.mysql.plist
Or, if you don't want/need launchctl, you can just run:
  mysql.server start

在我的情况下，我现在通过launchctl load加载mysql ~/Library/LaunchAgents/homebrew.mx .mysql。Plist，然后能够启动$ mysql和我的方式。

在我的mac m1 macOS Monterey上安装MySQL后，使用brew安装MySQL，我得到了以下信息:

[System] [MY-013169] [Server] /opt/homebrew/Cellar/mysql/8.0.27_1/bin/mysqld (mysqld 8.0.27) initializing of server in progress as process 3624

[ERROR] [MY-010457] [Server] --initialize specified but the data directory has files in it. Aborting.

[ERROR] [MY-013236] [Server] The designated data directory /opt/homebrew/var/mysql/ is unusable. You can remove all files that the server added to it.

[ERROR] [MY-010119] [Server] Aborting

[System] [MY-010910] [Server] /opt/homebrew/Cellar/mysql/8.0.27_1/bin/mysqld: Shutdown complete (mysqld 8.0.27)  Homebrew.

还有这个警告:

Warning: The post-install step did not complete successfully You can
try again using:   brew postinstall mysql

之后，我尝试使用brew services启动MySQL，我得到了这个错误:

ERROR 2002 (HY000): Can't connect to local MySQL server through socket
'/tmp/mysql.sock' (2)

我设法修复它使用:

> rm -rf ~/opt/homebrew/var/mysql/
> brew postinstall mysql

现在您可以使用mysql -uroot或mysql -uroot -p连接。

如果你正在使用Kali linux，你可能需要显式地指定主机

用 Mysql -h 127.0.0.1 -u root 127.0.0.1是您的本地主机

我花了好长时间才想明白。我在评论里看到的。在使用brew安装mysql后，启动服务(可能使用sudo brew services start mysql)，然后运行:

$ mysqld

MySQL应该在后面为你运行。