请各位好心人帮帮小弟我,多谢

请各位好心人帮帮我,谢谢
我在数据库中有几行,我想把某列的值做加法,再显示到Label中,相加我会,但是不知道怎么显示在Label中,我是用C#的,不知道谁能帮我一下,谢谢  
string   sql   =   "select   sum(price)   from   tr   where   usersname= ' "   +   Session[ "logusername "].ToString()   +   " ' ";  
  OleDbCommand   cmd   =   new   OleDbCommand(sql,   conn);  
接下来代码该怎么写呢?


------解决方案--------------------------------------------------------
string str=cmd.ExecuteScalar().ToString();
------解决方案--------------------------------------------------------
this.label1.text=cmd.ExecuteScalar().tostring();
------解决方案--------------------------------------------------------
object obj = cmd.ExecuteScalar();
if (obj != DBNull.Value)
{
string ret = obj.ToString();
}
------解决方案--------------------------------------------------------
label1.text=cmd.ExecuteScalar().tostring();