Getting an error "record type has not been registered" in postgresql. What is wrong?

Question

CREATE OR REPLACE FUNCTION get_biggest_order()
RETURNS TABLE(CustomerID int,Sum float) AS
$$
DECLARE
    rec RECORD;
mycursor CURSOR FOR WITH TOTAL(TotalPerCustomer) AS (SELECT SUM(TotalDue) FROM SalesOrderHeader GROUP BY SalesOrderHeader.CustomerID),
    MAX(Max) AS (SELECT MAX(TotalPerCustomer) FROM TOTAL)
    SELECT SalesOrderHeader.CustomerID,SUM(TotalDue) AS S FROM SalesOrderHeader,MAX GROUP BY SalesOrderHeader.CustomerID,Max HAVING SUM(TotalDue)=Max;
    BEGIN
        CREATE TEMP TABLE Results2(CustomerID int,Sum float);
        -- Open the cursor
        OPEN mycursor;
        LOOP
            -- fetch row into the film
            FETCH mycursor INTO rec;
            -- exit when no more row to fetch
            EXIT WHEN NOT FOUND;
            -- build the output
            INSERT INTO Results2 SELECT (rec).*;
        END LOOP;
    -- Close the cursor
        CLOSE mycursor;
        RETURN QUERY EXECUTE 'SELECT * FROM Results2';
    END; $$
LANGUAGE plpgsql;

SELECT get_biggest_order();

Getting the following error in Postgres:

ERROR:  record type has not been registered
CONTEXT:  SQL statement "INSERT INTO Results2 SELECT (rec).*"
PL/pgSQL function get_biggest_order() line 17 at SQL statement
********** Error **********

ERROR: record type has not been registered
SQL state: 42809
Context: SQL statement "INSERT INTO Results2 SELECT (rec).*"
PL/pgSQL function get_biggest_order() line 17 at SQL statement

I am trying to return the query within the cursor in table format using the cursor. Apparently something is wrong with the record type variable and it cannot insert it into the temp table which i want to return using the function. What is wrong?

Answer 1

rec is an untyped record, so replace SELECT (rec).* with VALUES (rec.CustomerID, rec.S).