挑错

Question

unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, Buttons, ComCtrls, DB, ADODB;type
  TForm1 = class(TForm)
    ADOConnection1: TADOConnection;
    ADOQuery1: TADOQuery;
    ADOQuery2: TADOQuery;
    TreeView1: TTreeView;
    SpeedButton1: TSpeedButton;
    procedure SpeedButton1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;var
  Form1: TForm1;implementation{$R *.dfm}procedure TForm1.SpeedButton1Click(Sender: TObject);
var
  node:TTreeNode;
begin
  TreeView1.Items.Clear;
  node:=TreeView1.Items.Add(nil,'sss');
  with ADOQuery1 do
     begin
       close;
       sql.Clear;
       sql.Add('select distinct gloType from collects');
       open;
       if not eof then
          with ADOQuery2 do
            begin
               close;
               sql.Clear;
               sql.Add('select distinct Title from collects where gloType= '+ADOQuery1.fieldbyname('glotype').asstring);
               open;
            end;     end;end;end.
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错误提示：参数 软件下载 没有默认值
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有没有可能是数据库设置的问题？？？？

Answer 1

sql.Add('select distinct Title from collects where gloType= '+ADOQuery1.fieldbyname('glotype').asstring);
这句有问题，该为：
  sql.Add('select distinct Title from collects where gloType= '+quoted(ADOQuery1.fieldbyname('glotype').asstring));