On Fri, Jan 28, 2005 at 02:35:21 -0800,
Ron Mayer <rm_pg(at)cheapcomplexdevices(dot)com> wrote:
>
> Should the expressions
> select distinct x from t
> and
> select x from t group by x
> have the same effect?
>
> It seems the optimizer sometimes chooses different plans for those
> expressions. Could the select distinct have used the slightly
> faster hash aggregate?
I don't think select distinct can use hash aggregate plans.