在编辑框中输入字符串，如何在access中查找有与该字符串相符字段的纪录。

Question

edouserid:=username.Text;
edopassword:=password.Text;
with adoquery1 do
   begin
     close;
     sql.Text:='select * from userdata where userid=edouserid';
     open;
     if  eof then
         ShowMessage('无该用户!');
     if adoquery1.FieldByName('password').AsString<>edopassword then
         ShowMessage('密码不对!');
   end;
end;
运行时提示edouseerid没有默认值。

Answer 1

edouserid:=username.Text;
edopassword:=password.Text;
with adoquery1 do
   begin
     close;
     sql.Text:=format('select * from userdata where userid=''%s''',[edouserid]));
     open;
     if  eof then
         ShowMessage('无该用户!');
     if adoquery1.FieldByName('password').AsString<>edopassword then
         ShowMessage('密码不对!');
   end;

Answer 2

edouserid:=username.Text;
edopassword:=password.Text;
with adoquery1 do
   begin
     close;
     sql.Text:='select * from userdata where userid=:edouserid';  // :edouserid
     Parameters.ParamByName('edouserid').Value:=edouserid;  
     open;
     if  eof then
         ShowMessage('无该用户!');
     if adoquery1.FieldByName('password').AsString<>edopassword then
         ShowMessage('密码不对!');
   end;
end;

Answer 3

edouserid:=username.Text;
edopassword:=password.Text;
with adoquery1 do
   begin
     close;
     sql.Text:='select * from userdata where userid='''+edouserid+'''';//UserID为字符类型
或sql.Text:='select * from userdata where userid='+edouserid+'';//UserID为数字类型
     open;
     if  eof then
         ShowMessage('无该用户!');
     if adoquery1.FieldByName('password').AsString<>edopassword then
         ShowMessage('密码不对!');
   end;
end;

Answer 4

edouserid:=username.Text;
edopassword:=password.Text;
with adoquery1 do
   begin
     close;
     sql.clear;
     sql.Text:='select * from userdata where userid=:edouserid';
     sql.add(sql.text);
     Parameters.ParamByName('edouserid').Value:=edouserid; 
     open;
     if  eof then
         ShowMessage('无该用户!');
     if adoquery1.FieldByName('password').AsString<>edopassword then
         ShowMessage('密码不对!');
   end;
end;