> > SELECT controller_id FROM control
> > WHERE controller_id NOT IN
> > (SELECT DISTINCT controller_id FROM datapack);
> The DISTINCT is not necessary. I have heard with Oracle that DISTINCT is a
> huge performance problem. Is that true on PostgreSQL also?
>From my experience, it does not preform as well as the standard group by
>clause. I noticed a ~20%
increase in query run times.
Regards,
Richard Broersma Jr.
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