Обсуждение: Problem adding columns

I have two tables, from one of which I wish to obtain the sum of several columns (return1,....return7) and insert the result into the other.

Here are the tables layout:

CREATE TABLE investments
(
  investment_id serial NOT NULL,
  client_id integer,
  client_number integer,
  investment_date date,
  investment_amount integer,
  return1 integer,
  return2 integer,
  return3 integer,
  return4 integer,
  return5 integer,
  return6 integer,
  return7 integer
)


CREATE TABLE totalreturns
(
  client_name character varying(128),
  initial_invest numeric(8),
  total_reimburse numeric(8),
  difference numeric(7)
)


And the function to perform the aforementioned calculation:

CREATE FUNCTION add_reimburse(integer,integer,integer,integer,integer,integer,integer) RETURNS integer AS $$
DECLARE
    sumyields investments%rowtype;
    yields integer;
    client_count integer;
    counter integer;
BEGIN
    SELECT count(*) INTO client_count FROM investments;
    FOR counter IN 1 TO client_count
    LOOP
        yields:= sumyields.return1+sumyields.return2+sumyields.return3+sumyields.return4+sumyields.return5+sumyields.return6+sumyields.return7 ;
        INSERT INTO totalreturns(total_reimburse) VALUES(yields);
        yields:=0;
    END LOOP;
return counter;
END;
$$ language plpgsql;


The code is not resulting in any calculations inserted on the "recipient" table totalreturns.


Thank you in advance for any suggestions.


--
Regards

Oscar Alberto Chavarria
Mobile:          +506 814-0247

On Sun, Feb 11, 2007 at 09:16:36PM -0600, Oscar Alberto Chavarria Marin wrote:
> CREATE FUNCTION
> add_reimburse(integer,integer,integer,integer,integer,integer,integer)

Why does the function take all these parameters?  It doesn't do anything
with them.

>    SELECT count(*) INTO client_count FROM investments;
>    FOR counter IN 1 TO client_count
>    LOOP

Is this the actual code?  CREATE FUNCTION fails with a syntax error
in 8.0 and later, which presumably you're using since the function
has dollar quotes.  Perhaps you meant to do this (although a simpler
solution exists; see later):

FOR sumyields IN SELECT * FROM investments LOOP

>        yields:=
>
sumyields.return1+sumyields.return2+sumyields.return3+sumyields.return4+sumyields.return5+sumyields.return6+sumyields.return7
> ;

The table definition you showed doesn't have NOT NULL constraints
on these columns -- are any of the values NULL?  If so then their
sum will be NULL.  You might need to use COALESCE:

yields := COALESCE(sumyields.return1, 0) +
          COALESCE(sumyields.return2, 0) +
      ...

>        INSERT INTO totalreturns(total_reimburse) VALUES(yields);
>        yields:=0;

There's no need to set yields to 0 at the end of the loop when
you're going to be setting it at the beginning of the next loop.

>    END LOOP;
> return counter;
> END;
> $$ language plpgsql;

Are you aware of INSERT ... SELECT?  It looks like you're trying to
do this:

INSERT INTO totalreturns (total_reimburse)
SELECT COALESCE(return1, 0) + COALESCE(return2, 0) + COALESCE(return3, 0) +
       COALESCE(return4, 0) + COALESCE(return5, 0) + COALESCE(return6, 0) +
       COALESCE(return7, 0)
  FROM investments;

In PL/pgSQL you can get the number of affected rows with GET DIAGNOSTICS:

GET DIAGNOSTICS counter := ROW_COUNT;

--
Michael Fuhr