unit unit4;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, DB, Grids, DBGrids, DBTables, ExtCtrls, ComCtrls,
  Mask, DBCtrls, jpeg;

type
  TForm4 = class(TForm)
    Image1: TImage;
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    Label4: TLabel;
    Label5: TLabel;
    Label6: TLabel;
    Bevel1: TBevel;
    Label7: TLabel;
    Bevel2: TBevel;
    Label8: TLabel;
    Label9: TLabel;
    Label10: TLabel;
    Label11: TLabel;
    DBGrid1: TDBGrid;
    ComboBox1: TComboBox;
    Button1: TButton;
    Edit1: TEdit;
    Button2: TButton;
    DBEdit1: TDBEdit;
    DBEdit2: TDBEdit;
    DBEdit3: TDBEdit;
    DBEdit4: TDBEdit;
    Edit2: TEdit;
    Edit3: TEdit;
    Button3: TButton;
    DBGrid2: TDBGrid;
    Table1: TTable;
    DataSource1: TDataSource;
    Query1: TQuery;
    DataSource2: TDataSource;
    procedure FormCreate(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Label11Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form4: TForm4;

implementation

uses Unit1;

{$R *.dfm}

procedure TForm4.FormCreate(Sender: TObject);
begin
DBGrid1.Columns[2].Visible:=False;
DBGrid1.Columns[3].Visible:=False;
DBGrid1.Columns[4].Visible:=False;
end;

procedure TForm4.Button1Click(Sender: TObject);
begin
   if  ComboBox1.ItemIndex=2  then
      begin
           DBGrid1.Columns[2].Visible:=False;
           DBGrid1.Columns[4].Visible:=False;
           DBGrid1.Columns[3].Visible:=True;
     end
      else
      begin
     if  ComboBox1.ItemIndex=1   then
     begin
       DBGrid1.Columns[3].Visible:=False;
          DBGrid1.Columns[4].Visible:=False;
           DBGrid1.Columns[2].Visible:=True;
     end
     else
     begin
     if  ComboBox1.ItemIndex=0
     then
     begin
     DBGrid1.Columns[2].Visible:=False;
     DBGrid1.Columns[3].Visible:=False;
     DBGrid1.Columns[4].Visible:=True;
     end
     end
     end
end;

procedure TForm4.Button2Click(Sender: TObject);
begin
if Table1.Locate('學號',edit1.Text,[])then
begin
 label4.Visible:=True;
  label5.Visible:=True;
   label6.Visible:=True;
   label7.Visible:=True;
   DBEdit1.Visible:=True;
    DBEdit2.Visible:=True;
    DBEdit3.Visible:=True;
     DBEdit4.Visible:=True;
 end
else
 showMessage('對不起，您輸入的學號不存在！');
end;
procedure TForm4.Button3Click(Sender: TObject);
begin
 if  ComboBox1.ItemIndex=1  then  begin
 DBGrid2.Columns[3].Visible:=False;
          DBGrid2.Columns[4].Visible:=False;
           DBGrid2.Columns[2].Visible:=True;
query1.SQL.Clear;
query1.SQL.Add('select * from 學生信息');
query1.SQL.Add('where 英語成績 >='+Edit2.text);
query1.SQL.add('and 英語成績<='+Edit3.text);
query1.Open;
end;
 if  ComboBox1.ItemIndex=0  then  begin
  DBGrid2.Columns[2].Visible:=False;
           DBGrid2.Columns[4].Visible:=False;
           DBGrid2.Columns[3].Visible:=True;
query1.SQL.Clear;
query1.SQL.Add('select * from 學生信息');
query1.SQL.Add('where 語文成績 >='+Edit2.text);
query1.SQL.add('and 語文成績<='+Edit3.text);
query1.Open;
end;
 if  ComboBox1.ItemIndex=2  then  begin
 DBGrid2.Columns[2].Visible:=False;
     DBGrid2.Columns[3].Visible:=False;
     DBGrid2.Columns[4].Visible:=True;
query1.SQL.Clear;
query1.SQL.Add('select * from 學生信息');
query1.SQL.Add('where 數(shù)學成績 >='+Edit2.text);
query1.SQL.add('and 數(shù)學成績<='+Edit3.text);
query1.Open;
end;
DBGrid2.Visible:=true;
end;
procedure TForm4.Label11Click(Sender: TObject);
begin
form4.close;
form1.show;
end;

end.