Recursive PLPGSQL function?

From: "Mark Cave-Ayland" <m(dot)cave-ayland(at)webbased(dot)co(dot)uk>
To: <pgsql-general(at)postgresql(dot)org>
Subject: Recursive PLPGSQL function?
Date: 2004-08-04 16:17:08
Message-ID: 8F4A22E017460A458DB7BBAB65CA6AE5026627@openmanage
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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
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