Message-ID: <3F5C8EFB.7090101@fireserve.net>
Date: Mon, 08 Sep 2003 07:15:23 -0700
From: Dennis Gearon <gearond@fireserve.net>
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To: newsy@lewczuk.com
Cc: Lista dyskusyjna pgsql-general <pgsql-general@postgresql.org>,
	Lista dyskusyjna pgsql-sql <pgsql-sql@postgresql.org>,
	Lista dyskusyjna pgsql-bugs <pgsql-bugs@postgresql.org>
Subject: Re: [GENERAL] plPGSQL bug in function creation
References: <004901c375e3$bd31f660$4701a8c0@marek>
In-Reply-To: <004901c375e3$bd31f660$4701a8c0@marek>
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Marek Lewczuk wrote:

>Hello,
>I think that there is a bug in plPGSQL - or maybe I don't know something
>about this language. Try to create this function
>
>
>Ok., this is the function created in plPGSQL:
>
>CREATE FUNCTION "public"."test" (text, text) RETURNS text AS'
>BEGIN
>  IF $1 THEN
>    RETURN $1;
>  ELSE
>    RETURN $2;
>  END IF;
>END;
>'LANGUAGE 'plpgsql' VOLATILE CALLED ON NULL INPUT SECURITY INVOKER;
>
>If you will execute SELECT test('tess', 'erer') -> then "tess" will be
>returned. If you will execute: SELECT test(NULL, 'buuu'); -> then it
>will return NULL, but it should return "buuu". I tried to figure out why
>it is happening so i modifye this function to this:
>
>CREATE FUNCTION "public"."test" (text, text) RETURNS text AS'
>BEGIN
>  RETURN 'test';
>END;
>'LANGUAGE 'plpgsql' VOLATILE CALLED ON NULL INPUT SECURITY INVOKER;
>
>And when i execute: SELECT test(NULL, 'buuu'); -> it returns me NULL
>value, when it should return "buuu". Well I think that something is
>wrong here.
>
>If I will modify this function again to this:
>
>CREATE FUNCTION "public"."test" (varchar, varchar) RETURNS text AS'
>BEGIN
>  IF $1 THEN
>    RETURN $1;
>  ELSE
>    RETURN $2;
>  END IF;
>END;
>'LANGUAGE 'plpgsql' VOLATILE CALLED ON NULL INPUT SECURITY INVOKER;
>
>Everything is working OK.. So the problem is in TEXT type definition.
>
>I'm using PG 7.3.1 on Win/Cyg
>
>
> 
>
>---------------------------(end of broadcast)---------------------------
>TIP 8: explain analyze is your friend
>
>  
>
You can only test for NULL with 'IS NULL'.

NULL is NOT:
    FALSE, 0, or F