Re: Synopsis of SELECT statement: UNION, INTERSECTION, EXCEPT

2018-03-15 7:18 GMT-03:00 PG Doc comments form <noreply(at)postgresql(dot)org>:
> The following documentation comment has been logged on the website:
>
> Page: https://www.postgresql.org/docs/10/static/sql-select.html
> Description:
>
> The SYNOPSIS section of the "SELECT" SQL command contains the line
>
> [ { UNION | INTERSECT | EXCEPT } [ ALL | DISTINCT ] select ]
>
> (with a boldface "select"), but it is not clear what is meant by that
> "select". Further down the page, in the "UNION clause" section (and also
> INTERSECTION or EXCEPT), it is written:
>
"select" is defined as a sub-select that can appear in the FROM clause
(see the From Clause section).

> select_statement UNION [ ALL | DISTINCT ] select_statement
>
> which uses boldface "select_statement" instead of boldface "select" as in
> the synopsis. This is confusing.
>
It is a bug in the synopsis. UNION et al cannot contain some elements
(such as ORDER BY) that is allowed for a sub-select. The attached
patch replace "select" with the correct element ("select_statement").

--
Euler Taveira Timbira -
http://www.timbira.com.br/
PostgreSQL: Consultoria, Desenvolvimento, Suporte 24x7 e Treinamento