RE: to_number question

  • From: Wolfgang Breitling <breitliw@xxxxxxxxxxxxx>
  • To: oracle-l@xxxxxxxxxxxxx
  • Date: Thu, 15 Jul 2004 09:36:43 -0700

Of course it works. It is the proper way (without hints) of requesting (and 
ensuring) that Oracle to evaluate the subqueries on their own and not merging 
them with the rest of the query. Just as "order by" is the proper way of 
requesting (and ensuring) the resultrows to be returned in a particular order.

The basic tenet of relational databases, what I have tried to explain in this 
last series of posts, is that you must not assume any particular order of 
execution of your query, or components of your query. 
Any restructuring of the sql syntax is merely superficial, the fact that it 
sometimes works in causing the optimizer to change the access plan 
notwithstanding. It may quit working with the next upgrade to the optimizer.

Quoting Stephen.Lee@xxxxxxxx:

> > -----Original Message-----
> > One of the ways to make sure that a subquery is evaluated on 
> > its own and not 
> > flattened (unnested) into the whole query is to use the 
> > rownum pseudocolumn:
> I got around to trying this, and it works too.
> What a fine list group this is.


Wolfgang Breitling
Oracle 7,8,8i,9i OCP DBA
Centrex Consulting Corporation

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