Get page content by page id Wordpress

I have written a function and now I can fetch the content of any page or one more pages just by the page id.

<?php
 if(!function_exists('getPageContent'))
 {
  function getPageContent($pageId)
  {
   if(!is_numeric($pageId))
   {
    return;
   }
   global $wpdb;
   $sql_query = 'SELECT DISTINCT * FROM ' . $wpdb->posts .
   ' WHERE ' . $wpdb->posts . '.ID=' . $pageId;
   $posts = $wpdb->get_results($sql_query);
   if(!empty($posts))
   {
    foreach($posts as $post)
    {
     return nl2br($post->post_content);
    }
   }
  }
 }
?>

For exampe,

<?php echo getPageContent(6); ?>