/etc/my.conf中的
[client]
port = 3306
socket = /tmp/mysql.sock
[mysqld]
port = 3306
socket = /tmp/mysql.sock
和/etc/mysql/my.conf中socket=/var/run/mysqld/mysqld.sock 配置重復，導致/etc/mysql/my.conf中的[client]覆蓋了/etc/my.conf中的[client]設置，所以連接不正確，就會出現妳說的錯誤
最簡單的辦法是刪除這個文件
mv /etc/mysql/my.conf /etc/mysql/mysql.conf_backup