Re: PL/pgSQL PERFORM with CTE

On Tue, Aug 20, 2013 at 7:25 AM, Andres Freund <andres(at)2ndquadrant(dot)com> wrote:
> On 2013-08-20 14:15:55 +0200, David E. Wheeler wrote:
>> Hi Pavel,
>>
>> On Aug 20, 2013, at 2:11 PM, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> wrote:
>>
>> >> david=# DO $$
>> >> david$# BEGIN
>> >> david$# WITH now AS (SELECT now())
>> >> david$# PERFORM * from now;
>> >> david$# END;
>> >> david$# $$;
>> >> ERROR: syntax error at or near "PERFORM"
>> >> LINE 4: PERFORM * from now;
>> >> ^
>> >> Parser bug in PL/pgSQL, perhaps?
>> >
>> > no
>> >
>> > you cannot use a PL/pgSQL statement inside SQL statement.
>>
>> Well, there ought to be *some* way to tell PL/pgSQL to discard the result. Right now I am adding a variable to select into but never otherwise use. Inelegant, IMHO. Perhaps I’m missing some other way to do it?
>>
>> If so, it would help if the hint suggesting the use of PERFORM pointed to such alternatives.
>
> Not that that's elegant but IIRC PERFORM (WITH ...) ought to work. I
> don't think the intermingled plpgsql/sql grammars allow a nice way right
> now.

I think the way forward is to remove the restriction such that data
returning queries must be PERFORM'd.

merlin