Lee Fesperman <firstsql_at_ix.netcom.com> wrote in message news:<42A61E2E.21A_at_ix.netcom.com>...
> Bob Hairgrove wrote:
> >
> > On Tue, 07 Jun 2005 19:53:01 GMT, Lee Fesperman
> > <firstsql_at_ix.netcom.com> wrote:
> >
> > >Lastly, when using EXISTS the preferred form for the SELECT clause is 'SELECT *'.
> > >Unless the optimizer is crazy it should make no difference and is clearer.
> >
> > In Oracle versions 8 or lower, 'SELECT 1 ...' was also recommended ...
> > apparently, the server allocated memory for "*" columns or some such
> > nonsense, requiring it to query the table definition, whereas with
> > "SELECT 1" (or some other constant such as 'A') the engine didn't need
> > to touch the table at all.
>
> Oh well ... those 'crazy' optimizers ;^) Of course, the other parts of the query would
> also normally require accessing table definition to some degree.
>
> Thanks for sharing.
who can help me to optimize the sql 1?
Thanks in advanced!
Received on Wed Jun 08 2005 - 20:46:12 CDT
