ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2) resolved code example

Example 1: ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)

sudo chown -R _mysql:mysql /usr/local/var/mysql

sudo mysql.server start

Example 2: ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.s

> ln -s /var/lib/mysql/mysql.sock /tmp/mysql.sock
> 
> service mysql start or service mysql start

Example 3: error 2002 (hy000): can't connect to local mysql server through socket '/var/run/mysqld/mysqld.sock' (2)

mysql -h 127.0.0.1 -P 3306 -u root -p <database>