关于查询select

有db1.dob(user,admin)数据库，表user(user_id,user_name,user_pwd)里面有数据01,aaaa,12345

conn(连接文件）
表单中输入用户名：aaaa
          密  码：12345

exec="select * from user where user_name='"&trim(request.Form("name"))&"'"
rs.open exec,conn,1,1

if rs("user_name")<>trim(request.Form("name")) then'以下正确
             response.write("<script language=vbscript>"&"msgbox"&"""你输入的员工帐号不存在，请重输！"""&"</script>")
          response.write("<script>history.go(-1)</script>")  
       elseif rs("user_pwd")<>trim(request.Form("password")) then'以下正确
         response.write("<script language=vbscript>"&"msgbox"&"""你输入的密码错误，请重输！"""&"</script>")
         response.write("<script>history.go(-1)</script>")
       elseif trim(request.form("yzm"))<>trim(cstr(session("yzm_no"))) then
         response.write(session("yzm_no"))
         response.write("<script language=vbscript>"&"msgbox"&"""你输入的验证码错误，请重输！"""&"</script>")
         response.write("<script>history.go(-1)</script>")
       else
         session("adminname")=request.form("name")
         session("admin")="OK"
         response.write("<script language=vbscript>"&"msgbox"&"""欢迎您！管理员！请正确操作！"""&"</script>")
         if session("adminname")="admin" then
         response.write(session("adminname")&" 欢迎您进来管理！")
         end if
       end if      

这里判断不出用户名说，怎么回事。