在我的WSL(Ubuntu)中安装了mysql，试图进行命令行练习时，发现如下问题并解决。
安装mysql
apt-get install mysql-server mysql-client- 此时试图在shell中进入
mysql会报错如下：
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)
解决方法
使用如下命令即可：
sudo mkdir -p /var/run/mysqld
sudo chown mysql /var/run/mysqld/
sudo service mysql restart
问题原因分析
在WSL中，/var/run/mysqld/mysqld.sock文件不存在。执行vim /etc/mysql/my.cnf将会看到如下内容：
#
# The MySQL database server configuration file.
#
# You can copy this to one of:
# - "/etc/mysql/my.cnf" to set global options,
# - "~/.my.cnf" to set user-specific options.
#
# One can use all long options that the program supports.
# Run program with --help to get a list of available options and with
# --print-defaults to see which it would actually understand and use.
#
# For explanations see
# http://dev.mysql.com/doc/mysql/en/server-system-variables.html
#
# * IMPORTANT: Additional settings that can override those from this file!
# The files must end with '.cnf', otherwise they'll be ignored.
#
!includedir /etc/mysql/conf.d/
!includedir /etc/mysql/mysql.conf.d/
这里的mysql的配置在/etc/mysql/mysql.conf.d目录下的mysqld.cnf文件，打开可以看到:bind-address = 127.0.0.1 socket = /var/run/mysqld/mysqld.sock 等信息。
而WSL的/var/run下面没有mysqld目录，如果执行上述解决方法中的命令，目录和sock文件就都有了。
此时再输入mysql即可进入mysql的命令环境：
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 13
Server version: 8.0.20-0ubuntu0.20.04.1 (Ubuntu)
Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>
