ORA-00907: 缺少右括号，可能是子查询有问题

Posted 2023-03-31

【中文标题】ORA-00907: 缺少右括号，可能是子查询有问题

【英文标题】：ORA-00907: Missing right parenthesis ,maybe problem with SubQuery

【发布时间】：2019-05-19 08:30:43

【问题描述】：

这个查询报错

ORA-00907：缺少右括号

我找不到任何括号问题

   select 
    (select PRE_DESIG_ID FROM AUTHORIZATION 
         WHERE PROJECT_ID = 5 and PRE_DESIG_ID =48 and 
    ROWNUM=1 order by ID DESC) AS PERPARED_BY
    ,(Select PRE_LAST_DATE From (Select PRE_LAST_DATE From AUTHORIZATION  
    Where PROJECT_ID = 5 and PRE_DESIG_ID = 48 Order By ID Desc) 
    Where ROWNUM = 1) AS PRE_END_DT from AUTHORIZATION au
    LEFT join PROJECT p on AU.PROJECT_ID =p.PROJECT_ID
    LEFT join DESIGNATION d on au.AU_DESIG_ID=d.DESIGID;

【参考方案1】：

你的问题是这样的：

ORDER BY id DESC

您不能在充当列表达式的子查询中使用ORDER BY。如果您删除它，您所面临的错误就会消失。

但是，我希望您使用 with 子句重写您的查询，因为您的两个子查询表达式都获取同一行。

WITH auth AS ( SELECT *
                 FROM ( SELECT pre_desig_id AS perpared_by,
                    pre_last_date AS pre_end_dt
                        FROM authorization
                      WHERE project_id = 5
          AND pre_desig_id = 48 ORDER BY id DESC )
 WHERE ROWNUM = 1 )
SELECT a.perpared_by,a.pre_end_dt
  FROM authorization au
  LEFT JOIN project p ON au.project_id = p.project_id
  LEFT JOIN designation d ON au.au_desig_id = d.desigid
 CROSS JOIN auth a;

【讨论】：

对于 12.1 或更高版本的用户，fetch first row only 可以消除很多这种复杂情况。

【参考方案2】：

您需要将派生列的 (prepared_by) 子查询转换为类似于 pre_end_dt 的子查询，如下所示

Select 
       (Select pre_desig_id
          From (Select pre_desig_id,
                       row_number() over (order by ID desc) as rn
                  From Authorization
                 Where project_id = 5
                   and pre_desig_id = 48
                 )
         Where rn = 1)  as prepared_by,
       (Select pre_last_date
          From (Select pre_last_date,
                       row_number() over (order by ID desc) as rn
                  From Authorization
                 Where project_id = 5
                   and pre_desig_id = 48
                 )
         Where rn = 1) as pre_end_dt
  From Authorization au
  Left Join Project p
    on au.project_id = p.project_id
  Left Join Designation d
    on au.au_desig_id = d.desigid;

其中Order By ID Desc 部分产生错误，应该包含在额外的子查询中，否则编译器不允许直接使用Order By。即限制（rownum=1）和使用order by不允许在同一级别工作，它们需要分别存在于外部和内部选择语句中。

实际上，最好使用row_number()窗口解析函数而不是rownum伪列，因为它是在排序之前生成的，因此在大多数情况下是不可信的。

即使使用Where rownum = 1 和order by ID desc 进行内部选择语句也足够你使用，而是养成使用row_number() 函数的习惯。