Sys_refcursor vs collection parameter

Question

When providing a result set as a function parameter, are there any advantages/disadvantages to using a sys_refcursor vs a user-defined collection type?

Answer 1

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I was planning on iterating through the ref cursor and constructing a collection, then using table() to include it in the JOIN. Is that approach viable?
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No - Justin already told you to use a pipelined function. The function can be treated as a table just like you want.
Try this samle code in the SCOTT schema.
-- type to match emp record
create or replace type emp_scalar_type as object
  (EMPNO NUMBER(4) ,
   ENAME VARCHAR2(10),
   JOB VARCHAR2(9),
   MGR NUMBER(4),
   HIREDATE DATE,
   SAL NUMBER(7, 2),
   COMM NUMBER(7, 2),
   DEPTNO NUMBER(2)
-- table of emp records
create or replace type emp_table_type as table of emp_scalar_type
-- pipelined function
create or replace function get_emp( p_deptno in number )
  return emp_table_type
  PIPELINED
  as
   TYPE EmpCurTyp IS REF CURSOR RETURN emp%ROWTYPE;
    emp_cv EmpCurTyp;
    l_rec  emp%rowtype;
  begin
    open emp_cv for select * from emp where deptno = p_deptno;
    loop
      fetch emp_cv into l_rec;
      exit when (emp_cv%notfound);
      pipe row( emp_scalar_type( l_rec.empno, LOWER(l_rec.ename),
          l_rec.job, l_rec.mgr, l_rec.hiredate, l_rec.sal, l_rec.comm, l_rec.deptno ) );
    end loop;
    return;
  end;
select * from table(get_emp(20))Now you can join that 'table' to the dept table
SQL> select * from dept where deptno in (select deptno from table(get_emp(20)));
    DEPTNO DNAME          LOC
        20 RESEARCH       DALLAS
SQL>Isn't that what you said you wanted to do?