protected function _select(string $field, $as = FALSE): string
	{
		// Escape the identifiers
		$field = $this->driver->quoteIdent($field);

		if ( ! \is_string($as))
		{
			return $field;
		}

		$as = $this->driver->quoteIdent($as);
		return "({$field}) AS {$as} ";
	}