Re: [HACKERS] Re: [GENERAL] Re: [PHP3] Re: PostgreSQL vs Mysql comparison

> Bruce Momjian <maillist(at)candle(dot)pha(dot)pa(dot)us> writes:
> >> However, I can't see anything in the SQL92 spec that requires you to
> >> use HAVING intelligently, so maybe this error should be downgraded to
> >> a notice? "HAVING with no aggregates would be faster as a WHERE"
> >> (but we'll do it anyway to satisfy pedants...)
>
> > If we allow them, then people can do things like:
> > HAVING max(a) > b
>
> Er ... what's wrong with that? Assuming b is a group by column,
> of course...

But can we compare aggs and non-aggs? I see now that our code is fine:

select relowner
from pg_class
group by relowner
having max(relowner) = relowner;

This returns the proper result, namely the relowner _having_ the max
id.

Having is using an aggregate and non-aggregate, so when I said we only
support aggregates in the HAVING clause, I was wrong. Looks fine.

--
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