Recursive PLPGSQL function? - Mailing list pgsql-general

From Mark Cave-Ayland
Subject Recursive PLPGSQL function?
Date
Msg-id 8F4A22E017460A458DB7BBAB65CA6AE5026627@openmanage
Whole thread Raw
Responses Re: Recursive PLPGSQL function?  (Tom Lane <tgl@sss.pgh.pa.us>)
Re: Recursive PLPGSQL function?  (DeJuan Jackson <djackson@speedfc.com>)
List pgsql-general
Hi everyone,

I'm trying to write a recursive plpgsql function in PostgreSQL 7.4.2
that given a tree node id (ictid) will return all the nodes below it in
the tree, one row per node. When I try and execute the function I get
the following error message:

CONTEXT:  PL/pgSQL function "findsubcategories" line 15 at for over
select rows
PL/pgSQL function "findsubcategories" line 15 at for over select rows
PL/pgSQL function "findsubcategories" line 15 at for over select rows
PL/pgSQL function "findsubcategories" line 15 at for over select rows
...repeated many many times...


Can anyone see where I am going wrong in my function? I found a
reference to "for over select rows" in pl_funcs.c but it appears to be
denoting a statement type? The code is given below:


CREATE OR REPLACE FUNCTION plpgsql.findsubcategories(int8) RETURNS SETOF
inventory.cattree AS '
DECLARE
    _row inventory.cattree%ROWTYPE;
    _nrow inventory.cattree%ROWTYPE;
    _id ALIAS FOR $1;

BEGIN
    -- Select the starting tree entry
    FOR _row IN SELECT * FROM inventory.cattree WHERE parentictid =
_id LOOP

        -- Return this category
        RETURN NEXT _row;

        -- Recurse for each child function
        FOR _nrow IN SELECT * FROM
plpgsql.findsubcategories(_row.parentictid) LOOP
            RETURN NEXT _nrow;
        END LOOP;

    END LOOP;

    -- Return the entire set
    RETURN;
END
' LANGUAGE 'plpgsql';


If this is not possible, can anyone else suggest a way of getting the
required result?


Many thanks,

Mark.

---

Mark Cave-Ayland
Webbased Ltd.
Tamar Science Park
Derriford
Plymouth
PL6 8BX
England

Tel: +44 (0)1752 764445
Fax: +44 (0)1752 764446


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