What is a "simple expression"?

Started by PG Bug reporting formabout 4 years ago2 messagesdocs
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#1PG Bug reporting form
noreply@postgresql.org

The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/14/sql-select.html
Description:

Hi there

To start off I'd like to say your documentation is great and very helpful.
Thanks for that!

https://www.postgresql.org/docs/14/sql-select.html in the section "WINDOW
clause" talks about "simple expression." I couldn't find any explaining of
what actually constitutes a simple expression, not by searching for the term
or checking the index.

Cheers,
Damian

#2David G. Johnston
david.g.johnston@gmail.com
In reply to: PG Bug reporting form (#1)
Re: What is a "simple expression"?

On Wed, Apr 20, 2022 at 12:50 PM PG Doc comments form <
noreply@postgresql.org> wrote:

The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/14/sql-select.html
Description:

Hi there

To start off I'd like to say your documentation is great and very helpful.
Thanks for that!

https://www.postgresql.org/docs/14/sql-select.html in the section "WINDOW
clause" talks about "simple expression." I couldn't find any explaining of
what actually constitutes a simple expression, not by searching for the
term
or checking the index.

Yeah, "simple" there isn't a definitional word, it is there to make the
paragraph, which does qualify what the expression can be, read better.

You should be able to use, unless otherwise noted there or elsewhere, any
of the expression building components listed in the SQL Syntax chapter.
That chapter, for Window Functions, does further note that nesting window
functions isn't possible.

David J.