Обсуждение: Getting multiple rows in plpgsql function

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.

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

-- 
+----|        Roberto Mello   -    http://www.brasileiro.net/  |------+
+       Computer Science Graduate Student, Utah State University      +
+       USU Free Software & GNU/Linux Club - http://fslc.usu.edu/     +
And God said: E = ½mv² - Ze²/r, and there was light.

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
lowIS 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
sjoin 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
>