Re: cursors and function question

On Feb 13, 2018, at 1:22 PM, Adrian Klaver <adrian.klaver@aklaver.com> wrote:

On 02/13/2018 11:17 AM, armand pirvu wrote:

On Feb 13, 2018, at 12:54 PM, Adrian Klaver <adrian.klaver@aklaver.com<mailto:adrian.klaver@aklaver.com>> wrote:

On 02/13/2018 10:22 AM, armand pirvu wrote:

Hi
Is there any elegant way not a two steps way I can output the cursor value at each step?
testtbl table has this content
    col1    |    col2    | col3
------------+------------+------
 E1         | CAT1       |    0
 E1         | CAT2       |    0
 E1         | CAT3       |    0
 E4         | CAT1       |    0
 E5         | CAT1       |    0
 E6         | CAT1       |    0
 E7         | CAT1       |    0
This works
BEGIN WORK;
DECLARE fooc  CURSOR FOR SELECT * FROM testtbl;
FETCH ALL FROM fooc;
CLOSE fooc;
COMMIT WORK;
    col1    |    col2    | col3
------------+------------+------
 E1         | CAT1       |    0
 E1         | CAT2       |    0
 E1         | CAT3       |    0
 E4         | CAT1       |    0
 E5         | CAT1       |    0
 E6         | CAT1       |    0
 E7         | CAT1       |    0
But
CREATE OR REPLACE FUNCTION foofunc()
   RETURNS text AS $$
DECLARE
 var2   RECORD;
 cur CURSOR FOR SELECT * from testtbl;
BEGIN
   OPEN cur;
    LOOP
      FETCH cur INTO var2;
      return var2;
   END LOOP;
   CLOSE cur;
END; $$
LANGUAGE plpgsql;

CREATE OR REPLACE FUNCTION public.foofunc()
RETURNS SETOF testtbl
LANGUAGE sql
AS $function$
   SELECT * FROM testtbl;
$function$


test=> select * from foofunc();
col1 | col2 | col3
------+------+------
E1   | CAT1 |    0
E1   | CAT2 |    0
E1   | CAT3 |    0
E4   | CAT1 |    0
E5   | CAT1 |    0
E6   | CAT1 |    0
E7   | CAT1 |    0
(7 rows)

select foofunc();
            foofunc
-------------------------------
 ("E1        ","CAT1      ",0)
But I am looking to get
            foofunc
-------------------------------
 ("E1        ","CAT1      ",0)
 ("E1        ","CATs      ",0)
etc
Many thanks
— Armand

--
Adrian Klaver
adrian.klaver@aklaver.com <mailto:adrian.klaver@aklaver.com>

Thanks Adrian
That one I figured it out as well. The idea is that said table has some records which I need to loop and do some processing using cursors similar with
DECLARE
cur CURSOR FOR SELECT *
    FROM testtbl FOR UPDATE;
BEGIN
  FOR row IN cur LOOP
    UPDATE testtbl
    SET col3=1
    WHERE CURRENT OF cur;
  END LOOP;
  return cur;
END
For a row update the goal is to return the cursor value  be it before/after the update, hence my question and test

Not following, are you looking to do this in an UPDATE trigger or somewhere else?

Another way to ask is why do you want to use a cursor?

I found some code which seems to do what I need but it involves two functions
CREATE or replace FUNCTION reffunc(refcursor) RETURNS refcursor AS $$
BEGIN
    OPEN $1 FOR SELECT col FROM test;
    RETURN $1;
END;
$$ LANGUAGE plpgsql;
BEGIN;
SELECT reffunc('funccursor');
FETCH ALL IN funccursor;
COMMIT;
And this is what beats  me , aka can I put all in one / how ?
Thanks
Armand

-- 
Adrian Klaver
adrian.klaver@aklaver.com