Oracle学习：SQL & PL/SQL ORA-32039 错误

使用 WITH 子句作为虚拟表的时候，必须对查询的列添加别名，否则就会报错ORA-32039

例子： (需要添加列别名eid, emp_last, mgr_id, reportLevel):

WITH

  reports_to_101 (eid, emp_last, mgr_id, reportLevel) AS

  (

     SELECT employee_id, last_name, manager_id, 0 reportLevel

     FROM employees

     WHERE employee_id = 101

   UNION ALL

     SELECT e.employee_id, e.last_name, e.manager_id, reportLevel+1

     FROM reports_to_101 r, employees e

     WHERE r.eid = e.manager_id

  )

SELECT eid, emp_last, mgr_id, reportLevel

FROM reports_to_101

ORDER BY reportLevel, eid;