Jacques,
 
As I believe has been pointed out already it may possibly be more efficient
if dept is very small and emp is very large (especially if there are filters
and a join would be done before a filter was applied).  Alternatively it may
be that Oracle believe it is more intuitive to people with no preconceived
ideas.
 
Iain Nicoll
-----Original Message-----
Sent: 04 April 2003 20:24
To: Multiple recipients of list ORACLE-L



Why would you do that instead of 
SELECT emp.deptno, empno, ename 
FROM emp a, dept b 
WHERE dept.deptno = emp.deptno 
order by dept.deptname ; 

> -----Original Message----- 
> From: Nicoll, Iain [ mailto:[EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]> ] 
> 
> Don't really know but couldn't it be useful if you had 
>  
> ORDER BY ( SELECT deptname FROM dept 
>             WHERE dept.deptno = emp.deptno) 
>  
>  
> -----Original Message----- 
> From: Ashish [ mailto:[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> ] 
> 
> In Oracle 9.2.0.1, you can now order by using a single-row subquery 
> Here is an example: 
>  
> SELECT emp.deptno, empno, ename 
> FROM emp 
> ORDER BY ( SELECT deptno FROM dept 
>             WHERE dept.deptno = emp.deptno ); 
>  
> The question I have is what is the usefulness of this? Under which 
> circumstances 
> this can be used? 

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Author: Nicoll, Iain
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