登录数据库
想设计一个登录界面，用户输入正确的ID和password后提示‘欢迎’，输入有误时提示'用户名或密码有误'代码如下

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, Mask, DBCtrls, DB, ADODB;

type
TForm1 = class(TForm)
con1: TADOConnection;
qry1: TADOQuery;
ds1: TDataSource;
lbl1: TLabel;
lbl2: TLabel;
lbl3: TLabel;
btn1: TButton;
btn2: TButton;
edt1: TEdit;
edt2: TEdit;
procedure btn2Click(Sender: TObject);
procedure btn1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.btn1Click(Sender: TObject);
begin
qry1.Close;
qry1.SQL.Clear ;
qry1.SQL.Add('select ID,password from 信息表 where (edt1.text:=ID) and (edt2.text:=password)') ;
qry1.Open;
if (edt1.Text='ID') and (edt2.Text='password') then
ShowMessage('Welcom!')
else
ShowMessage('ID or password is wrong!');

end;
procedure TForm1.btn2Click(Sender: TObject);
begin
Close ;
end;

end.

运行后输入正确的id 和password 报错 [img=http://my.csdn.net/my/album/detail/1352267][/img]


[解决办法]
qry1.SQL.Add('select ID,password from 信息表 where (edt1.text:=ID) and (edt2.text:=password)') ;
qry1.Open;
if (edt1.Text=qry1.fieldbyname('ID').AsString) and (edt2.Text=qry1.fieldbyname('password').Asstring) then
ShowMessage('Welcom!')
else
ShowMessage('ID or password is wrong!');
[解决办法]

procedure TForm1.btn1Click(Sender: TObject);
begin
  qry1.Close;
  qry1.SQL.Clear ;
  qry1.SQL.Add('select 1 from 信息表 where ID=:A and password=:B');
  qry1.Parameters.ParamByName('A').Value:=edt1.text;
  qry1.Parameters.ParamByName('B').Value:=edt2.text;
  qry1.Open;
  if not qry1.IsEmpty then
    ShowMessage('Welcom!')
  else
    ShowMessage('ID or password is wrong!');
end;

[解决办法]

引用:

还是同样的错误

你把整个程序都发出来吧。。
[解决办法]
qry1.SQL.Add('select ID,password from 信息表 where ('+QuotedStr(edt1.text)+'=ID) and ('+QuotedStr(edt2.text)+'=password)') ;

qry1.Open;
if qry1.RecountCount > 0 then
ShowMessage('Welcom!')
else
ShowMessage('ID or password is wrong!');