PostgreSQL select into OUT variables

You can keep that as a SQL function if you want to. SQL functions can return multiple rows by running multiple SELECT queries, but they can only return multiple columns from the same query. So in order to keep that a SQL function, you need to use a single query that returns all the columns. This could be achieved with a common table expression:

CREATE FUNCTION public.getpogstats(IN p_symbol character varying, IN p_pogtypeid integer, OUT closehi numeric, OUT closelo numeric, OUT dayhi numeric, OUT daylo numeric, OUT s7dhi numeric, OUT s7dlo numeric, OUT t13hi numeric, OUT t13lo numeric, OUT close numeric, OUT firstdate timestamp without time zone)
    RETURNS record
    LANGUAGE sql
AS $function$
  with data1 as (
    SELECT ROUND(MAX(closeprice), 2) as closehi, 
           ROUND(MIN(closeprice), 2) as closelo, 
           ROUND(MAX(dayhigh), 2) as dayhi, 
           ROUND(MIN(daylow), 2) as daylo, 
           ROUND(MAX(sevendaydp), 2) as s7dhi, 
           ROUND(MIN(sevendaydp), 2) as s7dlo,
           ROUND(MAX(thirteendaydp), 2) as t13hi, 
           ROUND(MIN(thirteendaydp), 2) as t13lo, 
           MIN(datadate) as firstdate
    FROM pogdata
      JOIN symbol ON pogdata.symbolid = symbol.symbolid AND pogdata.pogtypeid = p_pogtypeid
    WHERE symbol.symbol = p_symbol
  ), data2 as (
    SELECT ROUND(closeprice, 2) as close
    FROM pogdata
      JOIN symbol ON pogdata.symbolid = symbol.symbolid
    WHERE datadate = (SELECT MAX(datadate) 
                      FROM pogdata 
                        JOIN symbol ON pogdata.symbolid = symbol.symbolid AND pogdata.pogtypeid = p_pogtypeid 
                      WHERE symbol.symbol = p_symbol)
    AND symbol.symbol = p_symbol
    LIMIT 1 -- just to be sure
  )
  select d1.closehi, d1.closelo, d1.dayhi, d1.daylo, d1.s7dhi, d1.s7dlo, d1.t13hi, d1.t13lo, d2.close, d1.firstdate
  from data1 as d1
    cross join data2 as d2;

$function$;

(I have the impression the two queries can be combined into one, but right now I can't think of a way to do that)

Note that if you want to have a result with multiple columns (rather then one column with multiple fields), you need to expand those explicitly.

The following select:

select getpogstats('foo', 1);

will return a single row with a single column containing multiple fields, something like:

getpogstats
-----------
(1,2,3,4,5,6,7,8,9,"2017-05-09 18:19:20")

because the function is declared as "RETURNS record".

However, if you want the result as individual columns, you need to use:

select (getpogstats('foo', 1)).*;

Then you'll get each column separately:

closehi | closelo | dayhi | ...
--------+---------+-------+----
      1 |       2 |     3 | ...

Typically, functions returning more then one column are easier to handle if you declare them as returns table (...):

CREATE FUNCTION public.getpogstats(p_symbol character varying, p_pogtypeid integer)
  returns table(closehi numeric, closelo numeric, dayhi numeric, daylo numeric, s7dhi numeric, s7dlo numeric, t13hi numeric, t13lo numeric, close numeric, firstdate timestamp without time zone)
  LANGUAGE sql
AS $function$
  with data1 as (
    SELECT ROUND(MAX(closeprice), 2) as closehi, 
           ROUND(MIN(closeprice), 2) as closelo, 
           ROUND(MAX(dayhigh), 2) as dayhi, 
           ROUND(MIN(daylow), 2) as daylo, 
           ROUND(MAX(sevendaydp), 2) as s7dhi, 
           ROUND(MIN(sevendaydp), 2) as s7dlo,
           ROUND(MAX(thirteendaydp), 2) as t13hi, 
           ROUND(MIN(thirteendaydp), 2) as t13lo, 
           MIN(datadate) as firstdate
    FROM pogdata
      JOIN symbol ON pogdata.symbolid = symbol.symbolid AND pogdata.pogtypeid = p_pogtypeid
    WHERE symbol.symbol = p_symbol
  ), data2 as (
    SELECT ROUND(closeprice, 2) as close
    FROM pogdata
      JOIN symbol ON pogdata.symbolid = symbol.symbolid
    WHERE datadate = (SELECT MAX(datadate) 
                      FROM pogdata 
                         JOIN symbol ON pogdata.symbolid = symbol.symbolid AND pogdata.pogtypeid = p_pogtypeid 
                      WHERE symbol.symbol = p_symbol)
    AND symbol.symbol = p_symbol
    LIMIT 1 -- just to be sure
  )
  select d1.closehi, d1.closelo, d1.dayhi, d1.daylo, d1.s7dhi, d1.s7dlo, d1.t13hi, d1.t13lo, d2.close, d1.firstdate
  from data1 as d1
    cross join data2 as d2;

$function$;

Then you can use:

select *
from getpogstats('foo', 1);

and the result will automatically have a "table like" structure.

I just had to change the language and add the BEGIN and END wrapper to the following and it all worked. Well, it worked to the point where I could execute the procedure. Thanks for the help.

CREATE FUNCTION public.getpogstats(IN symbol character varying, IN pogtypeid integer, OUT closehi numeric, OUT closelo numeric, OUT dayhi numeric, OUT daylo numeric, OUT s7dhi numeric, OUT s7dlo numeric, OUT t13hi numeric, OUT t13lo numeric, OUT close numeric, OUT firstdate timestamp without time zone)
    RETURNS record
    LANGUAGE 'plpgsql'

AS $function$
BEGIN
SELECT ROUND(MAX(closeprice), 2), ROUND(MIN(closeprice), 2), ROUND(MAX(dayhigh), 2), ROUND(MIN(daylow), 2), ROUND(MAX(sevendaydp), 2), ROUND(MIN(sevendaydp), 2),
    ROUND(MAX(thirteendaydp), 2), ROUND(MIN(thirteendaydp), 2), MIN(datadate) 
    INTO closehi, closelo, dayhi, daylo, s7dhi, s7dlo, t13hi, t13lo, firstdate
FROM pogdata
JOIN symbol ON pogdata.symbolid = symbol.symbolid AND pogdata.pogtypeid = pogtypeid
WHERE symbol.symbol = symbol;

SELECT ROUND(closeprice, 2) INTO close FROM pogdata
JOIN symbol ON pogdata.symbolid = symbol.symbolid
WHERE datadate = (SELECT MAX(datadate) 
                  FROM pogdata JOIN symbol ON pogdata.symbolid = symbol.symbolid AND pogdata.pogtypeid = pogtypeid 
                  WHERE symbol.symbol = symbol)
AND symbol.symbol = symbol;
END;
$function$;

ALTER FUNCTION public.getpogstats(character varying, integer)
    OWNER TO postgres;