select语句中的查询游标属性

Question

我试图在一个以游标为列的查询中设置where子句。

with w1 as (
select 1 pid, 'a1' pnm from dual union all
select 2 pid, 'b2' pnm from dual 
), w2 as (
select 1 pid, 10 cid, 'aa1' cnm from dual union all
select 1 pid, 20 cid, 'bb2' cnm from dual union all
select 1 pid, 30 cid, 'cc3' cnm from dual union all
select 2 pid, 11 cid, 'dd4' cnm from dual union all
select 2 pid, 12 cid, 'ee5' cnm from dual 
), w3 as (
select l.pid, l.pnm,
       cursor(select d.cid, d.cnm from w2 d where d.pid = l.pid) a  
  from w1 l
) 
select * 
  from w3 
 where a.cid = 11

这给了ORA-00904: "A"."CID": invalid identifier
甚至可以创建一个这样的where子句吗？
ver：Oracle 11gr2