On 2016-05-09 11:45, liviuslivius liviuslivius@...
[firebird-support] wrote:

> Hi,
>
> This is not specific to Firebird question but:
> is something in SQL standard specification about sorted fields must
> be
> also returned?
> I mean:
>
> SELECT
> [FILM_DATE,]FILM_TITLE
> FROM
> FILMS
> ORDER BY FILM_DATE, FILM_TITLE
>
> is [FILM_DATE] required by SQL standard or it is optional or SQL
> standard tell nothing about this?

I don't have the SQL standard at hand right now, so I can't double
check. As far as I know, the SQL standard allows you to sort on any
field, even if it is not in the select list (with the exception of
course of ordering by column index).

Mark