Re: Can't use WITH in a PERFORM query in PL/pgSQL? - Mailing list pgsql-bugs

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Subject Re: Can't use WITH in a PERFORM query in PL/pgSQL?
Date
Msg-id 29F36C7C98AB09499B1A209D48EAA615B501DA9401@mail2a.alliedtesting.com
Whole thread Raw
In response to Can't use WITH in a PERFORM query in PL/pgSQL?  (<depstein@alliedtesting.com>)
Responses Re: Can't use WITH in a PERFORM query in PL/pgSQL?  (Pavel Stehule <pavel.stehule@gmail.com>)
Re: Can't use WITH in a PERFORM query in PL/pgSQL?  (Bruce Momjian <bruce@momjian.us>)
Re: Can't use WITH in a PERFORM query in PL/pgSQL?  (Bruce Momjian <bruce@momjian.us>)
List pgsql-bugs
Update: It has been suggested to wrap perform around a select like this:

do
$$begin
perform(
with A as (select 1 as foo)
select foo from A
);
end$$;

This won't work if select returns more than one statement:

do
$$begin
perform(
with A as (select generate_series(1,3) as foo)
select foo from A
);
end$$;

   ERROR:  more than one row returned by a subquery used as an expression

So I still say it's broken.

(Sorry for top-posting: I am forced to use Outlook at work...)

From: Dmitry Epstein
Sent: Sunday, March 06, 2011 4:29 PM
To: 'pgsql-bugs@postgresql.org'
Cc: Peter Gagarinov; Vladimir Shahov
Subject: Can't use WITH in a PERFORM query in PL/pgSQL?

PostgreSQL 9.0.1

It seems that PostgreSQL doesn't understand the WITH construct when used in=
 a PERFORM query inside PL/pgSQL functions and code blocks:

Example:

do
$$begin
with A as (select 1 as foo)
perform foo from A;
end$$;

    syntax error at or near "perform"

do
$$begin
with A as (select 1 as foo)
select foo from A;
end$$;

    query has no destination for result data

The only workaround that I can think of is to use a dummy variable to captu=
re the query result. This has to be done even when the query doesn't have a=
 result (as when calling a function returning void).

do
$$declare
dummy record;
begin
with A as (select 1 as foo)
select foo into dummy from A;
end$$;


Dmitry Epstein | Developer

Allied Testing
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