学习SQL语句-Select（2）：指定表中的字段本⽂来⾃：万⼀
//选择 country 表中的 Name 字段
SELECT Name FROM country
//选择 country 表中的 Name、Area 和 Population 字段
SELECT Name,Area,Population FROM country
{多个字段时, 字段名是⽤ "," 隔开的}
本例效果图:
代码⽂件:
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, ExtCtrls, Grids, DBGrids, DB, ADODB;
type
TForm1 = class(TForm)
Panel1: TPanel;
Button1: TButton;
Button2: TButton;
DBGrid1: TDBGrid;
DataSource1: TDataSource;
ADODataSet1: TADODataSet;
procedure FormCreate(Sender: TObject);
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.Button1Click(Sender: TObject);
begin
with ADODataSet1 do begin
Close;
CommandText := 'SELECT Name FROM country';
Open;
end;
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
with ADODataSet1 do begin
Close;
CommandText := 'SELECT Name,Area,Population FROM country';
Open;
end;
end;
sql中select是什么意思
procedure TForm1.FormCreate(Sender: TObject);
var
mdbFile: string;
begin
mdbFile := GetEnvironmentVariable('COMMONPROGRAMFILES');
mdbFile := mdbFile + '\CodeGear Shared\Data\dbdemos.mdb';
ADODataSet1.ConnectionString := 'Provider=Microsoft.Jet.OLEDB.4.0;Data Source=' +
mdbFile + ';Persist Security Info=False';
DBGrid1.DataSource := DataSource1;
DataSource1.DataSet := ADODataSet1;
end;
end.

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