//数据库连接

define('DB_HOST','localhost');

define('DB_USER','root');

define('DB_PWD','root');

define('DB_NAME','rsp_hts');

//创建数据库连接

$_conn = @mysql_connect(DB_HOST,DB_USER,DB_PWD) or die('数据里连接失败');

//选择一款数据库

mysql_select_db(DB_NAME) or die('指定的数据库不存在');

//选择字符集

mysql_query('SET NAMES UTF8') or die('字符集错误');

//执行一条sql语句

mysql_query("SELECT tg_username FROM tg_user WHERE tg_username='{$_clean['username']}'") or die('SQL错误');