Re: How to find entries missing in 2nd table? - Mailing list pgsql-sql

> > 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.