http://www.postgresql.org/docs/current/static/functions-comparison.htmlThis document states this:
Lets assume:
A = NULL
B = 10
C = NULL
SELECT 1 WHERE A = B returns no rows
SELECT 1 WHERE A = C returns no rows (even though both A and C are NULL)
SELECT 1 WHERE A IS NOT DISTINCT FROM C returns 1 row.
essentially the third SQL statement works because it is equivalent to this:
SELECT 1 WHERE (A IS NULL AND C IS NULL) OR (A = C)
RobinsOn Fri, Feb 22, 2008 at 10:00 PM, johnf <
jfabiani@yolo.com> wrote:
On Friday 22 February 2008 01:35:47 am Bart Degryse wrote:
> Can you try this...
>
> CREATE OR REPLACE FUNCTION getfunctionaries(p_statecd integer)
> RETURNS SETOF t_functionaries AS
> $BODY$
> DECLARE
> rec t_functionaries%ROWTYPE;
> BEGIN
> FOR rec IN (
> SELECT f.functionaryid, f.category, f.description
> FROM functionaries f
> WHERE f.statecd IS NOT DISTINCT FROM p_statecd)
> LOOP
> return next rec;
> END LOOP;
> return;
> END;
> $BODY$
> LANGUAGE 'plpgsql' VOLATILE;
>
a newbie question. Could you explain why yours works? I don't understand how
it works if p_statecd = NULL
--
John Fabiani
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