I have a function that returns a SYS_REFCURSOR that has a single row but multiple columns. What I'm looking to do is to be able to have a SQL query that has nested sub-queries using the column values returned in the SYS_REFCURSOR. Alternative ideas such as types, etc would be appreciated. Code below is me writing on-the-fly and hasn't been validated for syntax.

--Oracle function
CREATE DummyFunction(dummyValue AS NUMBER) RETURN SYS_REFCURSOR
IS
  RETURN_DATA SYS_REFCURSOR;
BEGIN
  OPEN RETURN_DATA
  SELECT
    TO_CHAR(dummyValue) || 'A' AS ColumnA
    ,TO_CHAR(dummyValue) || 'B' AS ColumnB
  FROM
    DUAL;

  RETURN RETURN_DATA;
END;

--sample query with sub-queries; does not work
SELECT
  SELECT ColumnA FROM DummyFunction(1) FROM DUAL AS ColumnA
  ,SELECT ColumnB FROM DummyFunction(1) FROM DUAL AS ColumnB
FROM
  DUAL;