I have my query: ..

$di = FactoryDefault::getDefault();
    $builder = $di->get('modelsManager')->createBuilder();
    .... (Query builder)
       $a_menu =            builder ->getQuery()
                    ->execute()->toArray();

the result:

        array (size=67)
  0 => 
    array (size=9)
      'menu_module_ok' => string '1' (length=1)
      'menu_id' => string '2' (length=1)
      'menu_super_id' => null
      'menu_name' => string 'Administracion' (length=14)
      'menu_type' => string 'ITEM' (length=4)
      'menu_icon' => string 'icon-tasks' (length=10)
      'menu_url' => string '#' (length=1)
      'menu_option_key' => null
      'menu_option_value' => null
  1 => 
    array (size=9)
      'menu_module_ok' => string '1' (length=1)
      'menu_id' => string '11' (length=2)
      'menu_super_id' => string '20' (length=2)
      'menu_name' => string 'Archivos' (length=8)
      'menu_type' => string 'ITEM' (length=4)
      'menu_icon' => string 'icon-th' (length=7)
      'menu_url' => string '/private/file/index.html' (length=24)
      'menu_option_key' => null
      'menu_option_value' => null
  2 => 
    array (size=9)
      'menu_module_ok' => string '1' (length=1)
      'menu_id' => string '1' (length=1)
      'menu_super_id' => null
      'menu_name' => string 'Bienvenidos' (length=11)
      'menu_type' => string 'ITEM' (length=4)
      'menu_icon' => string 'icon-home' (length=9)
      'menu_url' => string '/private/welcome/index.html' (length=27)
      'menu_option_key' => null
      'menu_option_value' => null

but if i want that the key must be a particular column:

    $results = array();
    foreach ($a_menu as $key => $row) {
        $results[$row['menu_id']] = $row;
    }
    return $results;

The result:

    array (size=67)
  2 => 
    array (size=9)
      'menu_module_ok' => string '1' (length=1)
      'menu_id' => string '2' (length=1)
      'menu_super_id' => null
      'menu_name' => string 'Administracion' (length=14)
      'menu_type' => string 'ITEM' (length=4)
      'menu_icon' => string 'icon-tasks' (length=10)
      'menu_url' => string '#' (length=1)
      'menu_option_key' => null
      'menu_option_value' => null
  11 => 
    array (size=9)
      'menu_module_ok' => string '1' (length=1)
      'menu_id' => string '11' (length=2)
      'menu_super_id' => string '20' (length=2)
      'menu_name' => string 'Archivos' (length=8)
      'menu_type' => string 'ITEM' (length=4)
      'menu_icon' => string 'icon-th' (length=7)
      'menu_url' => string '/private/file/index.html' (length=24)
      'menu_option_key' => null
      'menu_option_value' => null
  1 => 
    array (size=9)
      'menu_module_ok' => string '1' (length=1)
      'menu_id' => string '1' (length=1)
      'menu_super_id' => null
      'menu_name' => string 'Bienvenidos' (length=11)
      'menu_type' => string 'ITEM' (length=4)
      'menu_icon' => string 'icon-home' (length=9)
      'menu_url' => string '/private/welcome/index.html' (length=27)
      'menu_option_key' => null
      'menu_option_value' => null
  79 => 
    array (size=9)
      'menu_module_ok' => string '1' (length=1)
      'menu_id' => string '79' (length=2)
      'menu_super_id' => string '56' (length=2)
      'menu_name' => string 'Buses' (length=5)
      'menu_type' => string 'ITEM' (length=4)
      'menu_icon' => string 'icon-home' (length=9)
      'menu_url' => string '/management/bus/index.html' (length=26)
      'menu_option_key' => null
      'menu_option_value' => null

Associative array of rows by menu_id

there is other way to do this?