mysql中文乱码

查看默认的编码格式:show variables like "%char%";
+--------------------------+----------------------------+
| Variable_name            | Value                      |
+--------------------------+----------------------------+
| character_set_client     | utf8                       |
| character_set_connection | utf8                       |
| character_set_database   | utf8                       |
| character_set_filesystem | binary                     |
| character_set_results    | utf8                       |
| character_set_server     | utf8                       |
| character_set_system     | utf8                       |
| character_sets_dir       | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+
8 rows in set (0.00 sec)

执行SET NAMES utf8的效果等同于同时设定如下：
SET character_set_client='utf8';
SET character_set_connection='utf8';
SET character_set_results='utf8';