代码文件:

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//分组条件可以是 Whereprocedure TForm1.Button1Click(Sender: TObject);begin  with ADODataSet1 do begin    Close;    CommandText := 'SELECT Continent, AVG(Area) AS 平均面积 ' +                   'FROM country WHERE Continent="South America" GROUP BY Continent';    Open;  end;end;//也可以是 Havingprocedure TForm1.Button2Click(Sender: TObject);begin  with ADODataSet1 do begin    Close;    CommandText := 'SELECT Continent, AVG(Area) AS 平均面积 ' +                   'FROM country GROUP BY Continent HAVING Continent<>"South America"';    Open;  end;end;

本文转自万一的博客