plpgsql question: select into multiple variables ?

Hi,



Postgres version 9.3.9


What is wrong with my usage of the plpgsql  "select into" concept
I have a function to look into a calendar table to find the first and
Last weekend date of a month.

In this simplified concept function I end up with a NULL for first or last weekend variable.


create or replace function sys.time_test ()
returns date as
$$
DECLARE
   first_weekend date;
   last_weekend date;
BEGIN

  SELECT MIN(CAL_DATE),MAX(CAL_DATE) INTO first_weekend::date, last_weekend::date FROM sys.calendar
          WHERE month_of_year = (extract(MONTH FROM current_date))::int AND
              year_of_date = (extract(YEAR FROM current_date))::int AND
             day_of_week IN ( 'Sat','Sun');

 RETURN( COALESCE(last_weekend,'01-jun-2014'));

END
$$
LANGUAGE plpgsql volatile;


If I execute the same select logic from a psql shell I get the correct result.


(1 row)

ace_db=# ace_db=#  SELECT MIN(CAL_DATE),MAX(CAL_DATE) FROM sys.calendar cal
                                                                               WHERE cal.month_of_year = (extract(MONTH
FROMcurrent_date))::int AND
        cal.year_of_date = (extract(YEAR FROM current_date))::int AND
                                                    cal.day_of_week IN ( 'Sat','Sun'); 
    min     |    max
------------+------------
 2015-06-06 | 2015-06-28
(1 row)


If I simplify to a single variable it works. i.e


create or replace function sys.time_test ()
returns date as
$$
DECLARE
   first_weekend date;
   last_weekend date;
BEGIN

  SELECT MIN(CAL_DATE) INTO first_weekend::date FROM sys.calendar
          WHERE month_of_year = (extract(MONTH FROM current_date))::int AND
              year_of_date = (extract(YEAR FROM current_date))::int AND
             day_of_week IN ( 'Sat','Sun');

 RETURN( COALESCE(first_weekend,'01-jun-2014'));

END
$$
LANGUAGE plpgsql volatile;



I suppose I can adjust to write my actual function to have 2 selects; one for each variable.
However, I thought according to the documentation the targets could/must match the result columns for select into ?


Thoughts


Thanks


Dave Day