Oracle SQL：UNION 子句上缺少表达式错误

Question

我有以下 SQL 查询：

SELECT CASE WHEN connect_by_isleaf = 1 THEN 0
        WHEN level = 1             THEN 1
        ELSE                           -1
   END AS status, 
   level, 
   name AS title, 
   NULL AS icon, 
   child_id   AS value, 
   NULL AS tooltip, 
   NULL AS link 
FROM (
   SELECT alu.arl_user_user_id AS child_id,
          alu.arl_list_list_id AS parent_id,
          '0'                  AS type,
         emp.employee_name    AS name
    FROM arl_list_user alu
    INNER JOIN arl_user au
            ON au.user_id = alu.arl_user_user_id
    INNER JOIN arl_active_emp emp
            ON au.arl_active_employee_id = emp.employee_id
  UNION
  SELECT all.arl_list_list_id  AS child_id,
         all.arl_list_list_id1 AS parent_id,
         '1'                   AS type,
         al.name               AS name
    FROM arl_list_list all
    INNER JOIN arl_list al
            ON al.list_id = all.arl_list_list_id
) table
START WITH child_id IN (
  SELECT child_id
    FROM table
    WHERE type = '1'
)
CONNECT BY PRIOR child_id = parent_id

这会导致解析错误：

ORA-06550：第 21 行，第 1 列：ORA-00936：缺少表达式。

我做了一些谷歌搜索，看起来“缺少表达式”通常意味着查询在某处缺少 FROM 子句，或者在 UNION 的情况下，两个联合查询的列数不同.我很确定这里不是这种情况，我无法弄清楚真正的问题是什么。

Answer 1

请不要使用all 和table（以及许多其他保留字）作为表、列或子查询的别名...