public function alias(String $column, String $alias)
	{
		// if (!$this->getBinding('select') || empty($this->getBinding('select'))) {
			// Since this method cannot be used without the SELECT statement,
			// we will throw an exception if `SELECT` binding is null or false. 
			// throw new RuntimeException(sprintf('Cannot call aggregate function on empty select.'));
		// }
		$alias = str_replace($this->generator->getDisallowedChars(), '', $alias);
		return $this->attachSeparator($column . ' AS ' . $alias);
	}