Re: A question about PL/pgSQL DECLAREd variable behavior

From: Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com>
To: Dane Foster <studdugie(at)gmail(dot)com>
Cc: pgsql-general <pgsql-general(at)postgresql(dot)org>
Subject: Re: A question about PL/pgSQL DECLAREd variable behavior
Date: 2015-10-22 02:23:19
Message-ID: CAEepm=2Oq15ErmKZoVFEd=Grdjbm0CwVPoxZQiO1F68NmQxOMg@mail.gmail.com
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On Thu, Oct 22, 2015 at 2:48 PM, Dane Foster <studdugie(at)gmail(dot)com> wrote:
> I wrote the following simple function to try to learn what happens to a
> DECLAREd variable whose assignment comes from an INTO statement where the
> query being executed does not return a result.
>
> CREATE OR REPLACE FUNCTION _test() RETURNS BOOLEAN AS $$
> DECLARE r RECORD;
> BEGIN SELECT 1 AS one INTO r WHERE false; RETURN r IS NULL; END;
> $$ LANGUAGE plpgsql;
>
> The function returns true. Given that I can't find any explicit reference in
> the documentation about the behavior I've just described is it safe to
> assume that the current behavior is the expected behavior but it's just not
> documented?

http://www.postgresql.org/docs/9.4/static/plpgsql-statements.html#PLPGSQL-STATEMENTS-SQL-ONEROW

"If STRICT is not specified in the INTO clause, then target will be
set to the first row returned by the query, or to nulls if the query
returned no rows."

--
Thomas Munro
http://www.enterprisedb.com

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