Help with php and json

I'm having trouble displaying correctly in JSON , a result from two tables in my database.

The situation is as follows: I have requests in a table (A) and the products of that request in another table (B).

The JSON result I have is like this:

{
    "pedidos": [
            {
              "numOrc": "1",
              "nomeclie": "CONSUMIDOR",
              "valortotal": "2.077,20",
              "formapagto": "2",
              "emissao": "2013-02-15 16:09:11",
              "codprod": "4775",
              "qtdade": "1",
              "valorunit": "500,00",
              "tipopreco": "B"
             },
             {
              "numOrc": "2",
              "nomeclie": "MARCELO AUGUSTO BOTURA",
              "valortotal": "2.077,20",
              "formapagto": "2",
              "emissao": "2013-02-15 16:21:56",
              "codprod": "4775",
              "qtdade": "1",
              "valorunit": "500,00",
              "tipopreco": "B"
             }
            ]
}

As you can see, the result I have is only one product in each order. I needed the result to be as below (Warning for "tag Detalhes "):

{
    "pedidos": [
             {
              "numOrc": "2",
              "nomeclie": "MARCELO AUGUSTO BOTURA",
              "valortotal": "2.077,20",
              "formapagto": "2",
              "emissao": "2013-02-15 16:21:56",
              "Detalhes": 
               [
                {
                 "codprod": "4775",
                 "qtdade": "1",
                 "valorunit": "500,00",
                 "tipopreco": "B"
                },
                {
                 "codprod": "5555",
                 "qtdade": "3",
                 "valorunit": "800,00",
                 "tipopreco": "A"
                }
               ]
             }
            ]
}

My PHP code looks like this:

$sqlcode2 = mysql_query("Select a.numero as numOrc, a.nomeclie, a.valortotal, a.formapagto, a.emissao, b.codprod, b.qtdade, b.valorunit, b.tipopreco from orcamento a, prodorc b");


$jsonObj= array();


if($something == 'all')
 {  
   while($result=mysql_fetch_object($sqlcode2))
  {
   $jsonObj[] = $result;
   $teste= array('pedidos' => $jsonObj);
  }
 }

$final_res =json_encode($teste);
echo $final_res;