MySQL 5.7，將字符編碼統一改成utf8

修改配置文件my.ini 在 [mysqld] 下面添加兩行：

character_set_server=utf8
collation-server=utf8_general_ci

可能還需要這些配置：

[mysql]
default-character-set = utf8

[mysql.server]
default-character-set = utf8

[mysqld_safe]
default-character-set = utf8

[client]
default-character-set = utf8