json_encoder

<?php
 $hostname = "127.0.0.1";
 $username = "wordpress";
 $password = "wordpress";
 $db = "preventivi";

 $conn = mysqli_connect($hostname, $username, $password, $db) or die(mysqli_connect_error());
 if (mysqli_connect_errno()) {
   echo "Connessione fallita: " . die(mysqli_connect_error());
 }

 $result = mysqli_query($conn, "SELECT * FROM categorie");
 $rows = array();

 while ($row = mysqli_fetch_array($result, MYSQLI_ASSOC)) {
   $rows[] = array(
      'id' => $row['id'],
      'nome' => $row['nome'],
      );
 }

 $result2 = mysqli_query($conn, "SELECT * FROM elementi");
 $rows2 = array();

 while ($row = mysqli_fetch_array($result2, MYSQLI_ASSOC)) {
   $rows2[] = array(
      'id' => $row['id'],
      'id_cat' => $row['id_cat'],
      'nome' => $row['nome'],
      );
 }

 $result3 = mysqli_query($conn, "SELECT * FROM opzioni");
 $rows3 = array();

 while ($row = mysqli_fetch_array($result3, MYSQLI_ASSOC)) {
   $rows3[] = array(
      'id' => $row['id'],
      'id_elemento' => $row['id_elemento'],
      'nome' => $row['nome'],
      'prezzo' => $row['prezzo'],
      );
 }

 while ($row = mysqli_fetch_array($result3, MYSQLI_ASSOC)) {
   $rows3[] = array(
      'id' => $row['id'],
      'id_elemento' => $row['id_elemento'],
      'nome' => $row['nome'],
      'prezzo' => $row['prezzo'],
      );
 }

 echo "<pre>";
 print_r($rows) . "<br />" . print_r($rows2) . "<br />" . print_r($rows3);
 echo "</pre>";

 //echo "<pre>" . json_encode($rows) . "</pre>";
 mysqli_free_result($result);
 mysqli_free_result($result2);
 mysqli_free_result($result3);

 //$file = fopen('results.json', 'w+');
 //fwrite($file, json_encode($rows1));
 //fclose($file);

 mysqli_close($conn);
?>