I believe that at one time it was faster to use count on a PK column, where the PK was made up of a single column.
At one point the optimizer was not quite smart enough to this itself. It's been quite some time ago, an old version of Oracle 7 I think.
In any case, it doesn't work that way now, and not worth spending too much time on.
Jared
On Mon, 14 Feb 2005 16:34:59 -0800, Joel Garry <joelgarry@(protected)> wrote: > Anthony Wilson wrote: > > >it's a myth according to the venerable Tom Kyte. The SQL engine > silently rewrites >count(1) to count(*): > > Funny, he mentions that is a fact, but I've missed the reference to > where the fact is shown. Though I'm inclined to believe anything Tom > says, I find this particular one ironic in that he is talking about > facts and opinions when he says it. And I'm certainly glad he mentions > the differing case of 7.x, as that means I didn't get the myth > completely out of thin air or confused it with some other function. > Just means that old habits die hard. > > Joel Garry > http://www.garry.to > > > -- > http://www.freelists.org/webpage/oracle-l >
-- Jared Still Certifiable Oracle DBA and Part Time Perl Evangelist -- http://www.freelists.org/webpage/oracle-l
