错误提示分析原因给出解决方案

procedure TFrmLogin.BtnLoginClick(Sender: TObject);
begin
  with DM.query do
  begin
    close;
    sql.clear;
    sql.Add('select * from TB_Users where UserName=：UN and PassWord=:PW');
    ParamByName('UN').AsString:=CBUserName.Text;
    ParamByName('PW').AsString:=EDPassWord.Text;
    Open;
    if recordCount<1 then
    begin
        ShowMessage('对不起！用户名或密码错误！');
        Exit;
    end;
    pass:=true;
    self.Close;
  end;
end;


或：

procedure TFrmLogin.BtnLoginClick(Sender: TObject);
begin
  with DM.query do
  begin
    close;
    sql.clear;
    sql.Add('select * from TB_Users where UserName='''+CBUserName.Text+''' and PassWord='''+EDPassWord.Text+''');
    Open;
    if recordCount<1 then
    begin
        ShowMessage('对不起！用户名或密码错误！');
        Exit;
    end;
    pass:=true;
    self.Close;
  end;
end;

注意中英文输入法！