unit1.pas

sql2000工程实践一书第14张源代码

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, Grids, DBGrids, DB, ADODB;

type
  TForm1 = class(TForm)
    ADOQuery1: TADOQuery;
    DataSource1: TDataSource;
    DBGrid1: TDBGrid;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
ADOQuery1.Close;//断开数据连接
ADOQuery1.SQL.Clear;//清除SQL语句
//添加SQL语句
ADOQuery1.SQL.Add('select 姓名,语文,数学,英语,物理,化学,语文+数学'+
                  '+英语+物理+化学 as 总分 from Student where'+
                  '(语文+数学+英语+物理+化学)>400');
ADOQuery1.Open;//与数据库建立连接
end;

end.