Re: Find min and max values across two columns?

Amos Hayes <ahayes@polkaroo.net> writes:
> I'm trying to build a query that among other things, returns the  
> minimum and maximum values contained in either of two columns.

I think you might be looking for
select greatest(max(columnA), max(columnB)) from tab;select least(min(columnA), min(columnB)) from tab;

greatest/least are relatively new but you can roll your own in
older PG releases.
        regards, tom lane