code: public static function countPublishedBySourceAndParent($strSource, $intParent, array $arrOptions=array())
  	{
  		$t = static::$strTable;
  		$arrColumns = array("$t.source=? AND $t.parent=?");
  
  		if (!static::isPreviewMode($arrOptions))
  		{
  			$arrColumns[] = "$t.published='1'";
  		}
  
  		return static::countBy($arrColumns, array($strSource, (int) $intParent));
  	}
docs: Count published comments by their source table and parent ID
  
  @param string  $strSource  The source element
  @param integer $intParent  The parent ID
  @param array   $arrOptions An optional options array
  
  @return integer The number of comments