On Wed, 13 Jul 2022 at 05:31, Tom Lane <t...@sss.pgh.pa.us> wrote: > I tried the attached quick-hack patch that just prevents > remove_useless_groupby_columns from removing anything that > appears in ORDER BY. That successfully fixes the complained-of > case, and it doesn't change any existing regression test results. > I'm not sure whether there are any cases that it makes significantly > worse.
In addition to this, we also do a pre-verification step to see if the ORDER BY has anything in it that the GROUP BY does not? I don't think there's any harm in removing the GROUP BY item if the pre-check finds something extra in ORDER BY since preprocess_groupclause() is going to fail in that case anyway. David
