Re: Strange error message when reference non-existent column foo."count"

Sorry, I changed the email as I was writing it but I forgot to change the
subject line. An appropriate subject would be 'Strange behavior when
referencing non-existent column foo."count".'

On Wed, Dec 17, 2014 at 2:50 PM, Patrick Krecker <patrick(at)judicata(dot)com>
wrote:
>
> I encountered this today and it was quite surprising:
>
> select version();
> version
>
>
> ------------------------------------------------------------------------------------------------------
> PostgreSQL 9.3.5 on x86_64-unknown-linux-gnu, compiled by gcc (Ubuntu
> 4.8.2-19ubuntu1) 4.8.2, 64-bit
>
> create table foo as (select generate_series(1,3));
>
> As expected, the following fails:
>
> select count from foo;
> ERROR: column "count" does not exist
> LINE 1: select count from foo;
> ^
> But if I change the syntax to something I thought was equivalent:
>
> select foo."count" from foo;
> count
> -------
> 3
> (1 row)
>
> It works! This was quite surprising to me. Is this expected behavior, that
> you can call an aggregate function without any parentheses (I can't find
> any other syntax that works for count() sans parentheses, and this behavior
> doesn't occur for any other aggregate)?
>