public static function convertOrderField($table, $field)
	{
		$objDatabase = Database::getInstance();

		// Get the non-empty rows
		$objRow = $objDatabase->query("SELECT id, $field FROM $table WHERE $field LIKE '%,%'");

		// Convert the comma separated lists into serialized arrays
		while ($objRow->next())
		{
			$objDatabase->prepare("UPDATE $table SET $field=? WHERE id=?")
						->execute(serialize(explode(',', $objRow->$field)), $objRow->id);
		}

		static::convertMultiField($table, $field);
	}