"Erik G. Burrows" <eburrows(at)erikburrows(dot)com> writes:
> I need to get the most recent transaction for each customer. I need only
> the transaction ID, but the entire row would be best.
If you don't mind a not-standard-SQL solution, the SELECT DISTINCT ON
construct is designed for this sort of thing. See the "weather report"
example in the SELECT reference page.
regards, tom lane