ORA-32031: illegal reference of a query name in WITH clause

Question

Oracle tutorial : http://www.oracle.com/technology/pub/articles/hartley-recursive.html#4
When Executing this Query 6: Using a Recursive WITH Clause
WITH C (CNO, PCNO, CNAME) AS
(SELECT CNO, PCNO, CNAME -- initialization subquery
FROM COURSEX
WHERE CNO = 'C22' -- seed
UNION ALL
SELECT X.CNO, X.PCNO, X.CNAME -- recursive subquery
FROM C, COURSEX X
WHERE C.PCNO = X.CNO)
SELECT CNO, PCNO, CNAME
FROM C;
Error: ORA-32031: illegal reference of a query name in WITH clause
kindly suggest what need to do in case of recursion using subquery

Answer 1

SCOTT@orcl> ed
Wrote file afiedt.buf
  1  with c as
  2  (
  3  select empno,ename from emp
  4  where deptno=20
  5  union all
  6  select c.empno,c.ename from emp c
  7  where c.deptno=30
  8  )
  9* select * from c
SCOTT@orcl> /
     EMPNO ENAME
      7566 xx
      7788 xx
      7876 xx
      7902 xx
      7499 xx
      7521 xx
      7654 xx
      7698 xx
      7844 xx
      7900 xx
10 rows selected.
SCOTT@orcl> ed
Wrote file afiedt.buf
  1  with emp as
  2  (
  3  select empno,ename from emp
  4  where deptno=20
  5  union all
  6  select c.empno,c.ename from emp c
  7  where c.deptno=30
  8  )
  9* select * from emp
SCOTT@orcl> /
select empno,ename from emp
ERROR at line 3:
ORA-32031: illegal reference of a query name in WITH clause
SCOTT@orcl>You can not use the same table name alongwith WITH clause's cursor name. See as above if i says with C as... its works; but if i says with emp as... it returned ora-32031, because it is the name of table.
HTH
Girish Sharma