Get Joomla article SEF url by article alias

joomla_article_sef.php

<?php
$db    = JFactory::getDbo();
$query = $db->getQuery(true);
$alias = 'title';

$query->select($query->quoteName(array('id', 'catid')))
  ->from($query->quoteName('#__content'))
  ->where($query->quoteName('alias') . ' = ' . $query->quote($alias));

$item = $db->setQuery($query)
  ->loadObject();

if (!empty($item))
{
  JLoader::register('ContentHelperRoute', JPATH_SITE . '/components/com_content/helpers/route.php');

  $item->link = JRoute::_(ContentHelperRoute::getArticleRoute($item->id . ':' . $alias, $item->catid));
}