oracle，添加子查询时缺少右括号答案

【问题标题】：oracle, missing right parenthesis when adding subqueryoracle，添加子查询时缺少右括号
【发布时间】：2016-02-02 03:52:14
【问题描述】：

内部查询如下，独立工作正常

select graduate.univid
from graduate, projectmanager, university
where graduate.empid = projectmanager.mgrid and rownum = 1
group by graduate.univid
order by count(graduate.univid) desc;

但是当作为子查询放置时，ORACLE sqlplus 不断给出“缺少右括号”的错误

select university.univname
from university
where exists 
(
select graduate.univid
from graduate, projectmanager, university
where graduate.empid = projectmanager.mgrid and rownum = 1
group by graduate.univid
order by count(graduate.univid)
);

我在 stackoverflow 上检查过类似的问题，但并没有真正的帮助

【问题讨论】：

由于各种原因，您的查询看起来不正确。它缺少连接条件（并且您应该始终使用明确的JOIN）。当您只获取一行时，您正在聚合。

标签： sql oracle

【解决方案1】：

你使用存在，所以你必须给出大学和子查询的条件。你错过了你得到错误我会猜对正确的查询：

select t1.univname
from university t1
where exists 
(  select 1 from (
   select graduate.univid
   from graduate, projectmanager, university
   where graduate.empid = projectmanager.mgrid and rownum = 1
   group by graduate.univid
   order by count(graduate.univid)) t2 where t2.univid = t1.univid
);

【讨论】：

【解决方案2】：

假设你的其余逻辑是正确的，问题是order by 子句。您应该不在子查询中使用它。试试这个

select university.univname
from university
where exists 
(
select graduate.univid
from graduate, projectmanager, university
where graduate.empid = projectmanager.mgrid and rownum = 1
group by graduate.univid
);

您可以自己尝试一下。

此查询将返回1

select 1 from dual
where exists
(select 2 as id from dual)

但这会失败并给你ORA-00907: missing right parenthesis

select 1 from dual
where exists
(select 2 as id from dual order by id )

【讨论】：