Re: Getting multiple rows in plpgsql function

From: Guy Fraser <guy(at)incentre(dot)net>
To: pgsql-sql(at)postgresql(dot)org
Subject: Re: Getting multiple rows in plpgsql function
Date: 2003-01-25 01:42:39
Message-ID: 3E31EB8F.6040606@incentre.net
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NOTE: This is a feature in 7.3 it was either added or fixed, so you will not
be able to do this unless you are using version 7.3. Remember to backup with
pg_dumpall before you upgrade.

This is a sample sent to me earlier this week, that iterates an integer array:

########Cut Here########
CREATE TYPE group_view AS (grosysid int4, groname name, usesysid int4, usename
name);

CREATE OR REPLACE FUNCTION expand_groups() RETURNS SETOF group_view AS '
DECLARE
rec record;
groview record;
low int;
high int;
BEGIN
FOR rec IN SELECT grosysid FROM pg_group LOOP
SELECT INTO low
replace(split_part(array_dims(grolist),'':'',1),''['','''')::int
FROM pg_group WHERE grosysid = rec.grosysid;
IF low IS NULL THEN
low := 1;
high := 1;
ELSE
SELECT INTO high
replace(split_part(array_dims(grolist),'':'',2),'']'','''')::int
FROM pg_group WHERE grosysid = rec.grosysid;
IF high IS NULL THEN
high := 1;
END IF;
END IF;

FOR i IN low..high LOOP
SELECT INTO groview g.grosysid, g.groname, s.usesysid, s.usename
FROM pg_shadow s join pg_group g on s.usesysid = g.grolist[i]
WHERE grosysid = rec.grosysid;
RETURN NEXT groview;
END LOOP;
END LOOP;
RETURN;
END;
' LANGUAGE 'plpgsql' WITH ( iscachable, isstrict );

CREATE VIEW groupview AS SELECT * FROM expand_groups();
########Cut Here########

One of the tricks is that you apparently need to use the CREATE TYPE commands
to define the returned result. The veiw at the end just makes queries look
like a table is being queried rather than a function.

I hope this helps.

Roberto Mello wrote:
> On Fri, Jan 24, 2003 at 11:39:07AM -0800, David Durst wrote:
>
>>I am wondering how you would handle a select that returns multiple rows
>>in a plpgsql function?
>>
>>In other words lets say I wanted to iterate through the results in
>>the function.
>
>
> There are examples in the PL/pgSQL documentation that show you how to do it.
>
> -Roberto
>

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